Multilayer fiber reinforcement design for 3d printing

ABSTRACT

According to at least one aspect, embodiments of the invention provide a 3D printer comprising an anisotropic head that solidifies, along anisotropic toolpaths, fiber swaths having an anisotropic characteristic oriented relative to a trajectory of the anisotropic tool paths, an isotropic head that solidifies, along isotropic toolpaths, a substantially isotropic material, a motorized drive for moving the anisotropic head and a build plate supporting a printed part in at least three degrees of freedom, and a controller configured to control the 3D printer to build the printed part by solidifying the isotropic material along the isotropic tool paths, solidifying the anisotropic material in fiber swaths tracking a non-concentric set of anisotropic tool paths for at least a first sequence of parallel shells, solidifying the anisotropic material in fiber swaths tracking an outer concentric set of anisotropic tool paths for at least a second sequence of parallel shells.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/944,088, filed Nov. 17, 2015, the disclosure of which is hereinincorporated by reference in its entirety. U.S. patent application Ser.No. 14/944,088 claims the benefit under 35 U.S.C. §119(e) of U.S.provisional application Ser. No. 62/172,021 filed Jun. 5, 2015; and62/080,890 filed Nov. 17, 2014, the disclosures of which are hereinincorporated by reference in their entirety; and is a continuation inpart of U.S. patent application Ser. No. 14/491,439 filed Sep. 19, 2014,the disclosure of which is herein incorporated by reference in itsentirety. U.S. patent application Ser. No. 14/491,439 is acontinuation-in-part of each of U.S. patent application Ser. No.14/222,318, filed Mar. 21, 2014; U.S. patent application Ser. No.14/297,437, filed Jun. 5, 2014; and U.S. patent application Ser. No.14/333,881 [now U.S. Pat. No. 9,149,988], filed Jul. 17, 2014; thedisclosures of which are herein incorporated by reference in theirentirety. U.S. patent application Ser. No. 14/222,318 claims the benefitunder 35 U.S.C. §119(e) of U.S. provisional application Ser. No.61/880,129, filed Sep. 19, 2013; 61/881,946, filed Sep. 24, 2013;61/883,440, filed Sep. 27, 2013; 61/902,256, filed Nov. 10, 2013,61/907,431, filed Nov. 22, 2013; 61/804,235, filed Mar. 22, 2013;61/815,531, filed Apr. 24, 2014; 61/831,600, filed Jun. 5, 2013;61/847,113, filed Jul. 17, 2013, and 61/878,029, filed Sep. 15, 2013,the disclosures of which are herein incorporated by reference in theirentirety. U.S. patent application Ser. No. 14/297,437 claims the benefitunder 35 U.S.C. §119(e) of U.S. provisional application Ser. No.61/881,946, filed Sep. 24, 2013; 61/902,256, filed Nov. 10, 2013;61/831,600, filed Jun. 5, 2013; 61/847,113, filed Jul. 17, 2013, and61/878,029, filed Sep. 15, 2013. U.S. patent application Ser. No.14/297,437 is also a continuation-in-part of U.S. patent applicationSer. No. 14/222,318. U.S. patent application Ser. No. 14/333,881 is acontinuation-in-part of each of U.S. patent application Ser. No.14/222,318, filed Mar. 21, 2014 and U.S. patent application Ser. No.14/297,437, filed Jun. 5, 2014. This application also relates to U.S.patent application Ser. No. 14/944,093 entitled COMPOSITE FILAMENT 3DPRINTING USING COMPLEMENTARY REINFORCEMENT FORMATIONS, filed Nov. 17,2015 and incorporated herein by reference.

FIELD

Aspects relate to three dimensional printing.

BACKGROUND

“Three dimensional printing” as an art includes various methods such asStereolithography (SLA) and Fused Filament Fabrication (FFF). SLAproduces high-resolution parts, typically not durable or UV-stable, andis used for proof-of-concept work; while FFF extrudes through a nozzlesuccessive filament beads of ABS or a similar polymer.

In the art of “Composite Lay-up”, preimpregnated (“prepreg”) compositesheets of fabric impregnated with a resin binder are layered into amold, heated, and cured. In “Composite Filament Winding” sticky “tows”including multiple thousands of individual carbon strands are woundaround a custom mandrel to form a rotationally symmetric part.

There is no commercial or experimental technique for orienting fiberduring additive manufacturing to anisotropically improve properties ofthe finished part.

SUMMARY

In one embodiment, or embodiment of the invention, a method forgenerating three-dimensional toolpath instructions for a threedimensional printer may include receiving a three-dimensional geometrysliced into shells or layers. For each of a set of shells or layersdefining a portion of a 3D printed part, first isotropic fill tool pathsmay be generated for controlling an isotropic solidifying head tosolidify, along the isotropic fill tool paths, a substantially isotropicfill material. For each of an anisotropic fill subset of the set ofshells or layers defining the portion of the 3D printed part, firstanisotropic fill tool paths may be generated for controlling ananisotropic solidifying head to solidify, along the anisotropic toolpaths, a substantially anisotropic fill material having an anisotropiccharacteristic oriented relative to a trajectory of the anisotropic filltool path. From among the set of shells or layers defining the portionof the 3D printed part, a selection of an editing subset of shells orlayers may be received, the editing subset including at least part ofthe anisotropic fill subset. For each shell or layer of the editingsubset, one of second isotropic fill toolpaths different from the firstisotropic fill toolpaths and second anisotropic fill toolpaths differentfrom the first anisotropic fill toolpaths may be regenerated. As usedherein, a “solidifying head” may be a melting FFF or FDM depositionhead, a curing head, a curing laser or UV light or energy application, asolidifying droplet or powder or suspension jet, or the like. Only amatrix material and a fill material may be melted then solidified orcured or jetted to solidify, while a fiber reinforcement remainsunmelted and solid.

Optionally, the method may include regenerating, for each shell or layerof the editing subset, both second isotropic fill toolpaths differentfrom the first isotropic fill toolpaths and second anisotropic filltoolpaths different from the first anisotropic fill toolpaths.

Further optionally, the method may include applying a first generationrule defining the first isotropic fill tool paths for controlling theisotropic solidifying head to solidify, along the isotropic fill toolpaths, the substantially isotropic fill material. A second generationrule may be applied defining the first anisotropic fill tool paths forcontrolling the anisotropic solidifying head to solidify, along theanisotropic tool paths, the substantially anisotropic fill material.Optionally, the first and second generation rules govern mutuallyexclusive regions within each shell or layer of the set of shells orlayers defining a portion of a 3D printed part.

Alternatively, or in addition, a first generation rule may be applieddefining the first isotropic fill tool paths for controlling theisotropic solidifying head to solidify, along the isotropic fill toolpaths, the substantially isotropic fill material, and a secondgeneration rule may be applied defining the first anisotropic fill toolpaths for controlling the anisotropic solidifying head to solidify,along the anisotropic tool paths, the substantially anisotropic fillmaterial. A priority may be defined between the first and secondgeneration rules to determine, when the first and second generationrules govern conflicting regions within a shell or layer of the set ofshells or layers defining a portion of a 3D printed part, which of thefirst or second generation rule shall apply.

Further optionally, within a sequential set of three or more parallelshells or layers, a wall generation rule may be applied defining firstisotropic fill tool paths for controlling the isotropic solidifying headto solidify the substantially isotropic fill material as a contour wallof the part; and a quasi-isotropic generation rule may be applieddefining anisotropic fill tool paths for controlling the anisotropicsolidifying head to solidify the substantially anisotropic fill materialas a quasi-isotropic set of anisotropic fill tool paths forming alaminate among the three or more shells or layers and having a partiallyisotropic in-shell behavior among the three or more shells or layers.

Alternatively, or in addition, within the sequential set of three ormore parallel shells or layers, a volume infill generation rule may beapplied defining second isotropic fill tool paths for controlling theisotropic solidifying head to solidify the substantially isotropic fillmaterial as a volume infill of the part, or an outer concentricgeneration rule may be applied defining anisotropic fill tool paths forcontrolling the anisotropic solidifying head to solidify thesubstantially anisotropic fill material as concentric fill tool pathslocated adjacent and parallel to outer contour and/or outer perimeter ofthe part and at least partially radially outward from a centroid of the3D printed part.

Optionally, within the sequential set of three or more parallel shellsor layers, an inner concentric generation rule may be applied defininganisotropic fill tool paths for controlling the anisotropic solidifyinghead to solidify the substantially anisotropic fill material asconcentric fill tool paths located adjacent and parallel to innercontour and/or through-hole perimeters of the part.

In another embodiment, or embodiment of the invention, a printer foradditive manufacturing of a part may include an anisotropic solidifyinghead that solidifies, along anisotropic fill toolpaths, fiber swathsfrom a supply of anisotropic fiber reinforced material including aplurality of fiber strands extending continuously within a matrixmaterial, the fiber swaths having an anisotropic characteristic orientedrelative to a trajectory of the anisotropic fill tool paths. Anisotropic solidifying head may solidify, along isotropic fill toolpaths,a substantially isotropic material from a supply of solidifiableisotropic material. A motorized drive for relatively moving at least theanisotropic deposition head and a build plate supporting a 3D printedpart in three or more degrees of freedom. A controller may beoperatively connected to and configured to control the motorized drive,the anisotropic deposition head and the isotropic solidifying head, andmay control these to build the 3D printed part by solidifying theisotropic material along the isotropic fill tool paths, and/orsolidifying the anisotropic fill material in fiber swaths tracking anon-concentric set of anisotropic fill tool paths for at least a firstsequence of parallel shells. Further, the controller may control theseto solidify the anisotropic fill material in fiber swaths tracking anouter concentric set of anisotropic fill tool paths for at least asecond sequence of parallel shells. Each of the non-concentric set andthe outer concentric set of anisotropic tool paths may be located atleast partially radially outward from the centroid of the 3D printedpart. Again, a “solidifying head” may be a melting FFF or FDM depositionhead, a curing head, a curing laser or UV light or energy application, asolidifying droplet or powder or suspension jet, or the like. Only amatrix material and a fill material may be melted then solidified orcured or jetted to solidify, while a fiber reinforcement remainsunmelted and solid.

Optionally, a non-concentric set of anisotropic tool-paths includes aquasi-isotropic set of anisotropic fill tool paths forming a laminatehaving a partially isotropic in-shell behavior among three or moreshells, and the controller is further configured to control themotorized drive, the anisotropic deposition head and the isotropicsolidifying head to build the 3D printed part by solidifying theanisotropic fill material in fiber swaths tracking a quasi-isotropic setof anisotropic fill tool paths for at least the first sequence ofparallel shells.

In addition, or alternatively, the controller may be further configuredto control the motorized drive, the anisotropic deposition head and theisotropic solidifying head to build the 3D printed part by solidifyingthe anisotropic fill material in fiber swaths tracking a quasi-isotropicset of anisotropic fill tool paths for at least an additional sequenceof parallel shells separated from the first sequence of parallel shellsby a plurality of shells each including isotropic fill material.

Optionally, the non-concentric set of anisotropic tool-paths may includea set of complementary anisotropic fill tool paths of substantiallysimilar areal distribution, and the complementary anisotropic fill toolpaths may form a laminate having a combined in-shell behavior among twoor more shells. The controller may be further configured to control themotorized drive, the anisotropic deposition head and the isotropicsolidifying head to build the 3D printed part by solidifying theanisotropic fill material in fiber swaths tracking the set ofcomplementary anisotropic fill tool paths for at least the firstsequence of parallel shells.

Further optionally, the controller may be further configured to controlthe motorized drive, the anisotropic deposition head and the isotropicsolidifying head to build the 3D printed part by solidifying theanisotropic fill material in fiber swaths tracking an inner concentricset of anisotropic fill tool paths for at least one of the first orsecond sequence of parallel shells, the inner concentric set ofanisotropic tool paths being located surrounding one or more negativecontours or through hole within the 3D printed part.

Alternatively, or in addition, the controller may be further configuredto control the motorized drive, the anisotropic deposition head and theisotropic solidifying head to build the 3D printed part by solidifyingthe anisotropic fill material in fiber swaths tracking an innerconcentric set of anisotropic fill tool paths for at least one of thefirst or second sequence of parallel shells, the inner concentric set ofanisotropic tool paths being located looping an envelope shape includingat least two or more negative contours or through holes within the 3Dprinted part.

Further alternatively, or in addition, the controller may be furtherconfigured to control the motorized drive, the anisotropic depositionhead and the isotropic solidifying head to build the 3D printed part bysolidifying the anisotropic fill material in fiber swaths tracking acellular infill pattern of anisotropic fill tool paths for at least oneof the first or second sequence of parallel shells, the cellular infillpattern of anisotropic tool paths forming repeating and cellular wallsof anisotropic fill material within the 3D printed part.

Optionally, the controller may be further configured to control themotorized drive, the anisotropic deposition head and the isotropicsolidifying head to build the 3D printed part by solidifying theanisotropic fill material in fiber swaths tracking a self-crossingpattern of anisotropic fill tool paths for at least one of the first orsecond sequence of parallel shells, the self-crossing pattern ofanisotropic tool paths overlapping anisotropic solidification of fiberswaths within a same shell or layer.

In another embodiment, or embodiment of the invention, a machineimplemented method for generating three-dimensional toolpathinstructions for a three dimensional printer may include receiving athree-dimensional geometry sliced into shells or layers, and generatingisotropic fill tool paths for controlling an isotropic solidifying headto solidify, along the isotropic tool paths, a substantially isotropicfill material. The method may include generating anisotropic fill toolpaths for controlling an anisotropic solidifying head to solidify, alongthe anisotropic fill tool paths, a substantially anisotropic fillmaterial having an anisotropic characteristic oriented relative to atrajectory of the anisotropic fill tool path. This may includegenerating a non-concentric set of anisotropic fill tool paths for atleast a first sequence of parallel shells, the non-concentric set ofanisotropic fill tool paths being located at least partially radiallyoutward from the centroid of the three-dimensional geometry; and/orgenerating an outer concentric set of anisotropic fill tool paths atleast a second sequence of parallel shells, the concentric set ofanisotropic fill tool paths being located at least partially radiallyoutward from the centroid of the three-dimensional geometry; and/orcombining the isotropic fill tool paths and the anisotropic filltoolpaths into a sequence of tool paths defining a 3D printed part.Again, a “solidifying” may be performed melting FFF or FDM depositionhead, a curing head, a curing laser or UV light or energy application, asolidifying droplet or powder or suspension jet, or the like. Only amatrix material and a fill material may be melted then solidified orcured or jetted to solidify, while a fiber reinforcement remainsunmelted and solid.

Optionally, the non-concentric set of anisotropic tool paths includes aquasi-isotropic set of anisotropic fill tool paths forming a laminatehaving a partially isotropic in-shell behavior among three or morenested or parallel shells, further comprising generating aquasi-isotropic set of anisotropic fill tool paths for at least a firstsequence of three or more nested or parallel shells, the quasi-isotropicset of anisotropic fill tool paths being located at least partiallyradially outward from the centroid of the three-dimensional geometry

Alternatively, or in addition, the anisotropic fill material may besolidified in fiber swaths tracking a quasi-isotropic set of anisotropicfill tool paths for at least an additional sequence of parallel shellsseparated from the first sequence of parallel shells by a plurality ofshells each including isotropic fill material.

Further optionally, the non-concentric set of anisotropic tool-paths mayinclude a set of complementary anisotropic fill tool paths ofsubstantially similar areal distribution, the complementary anisotropicfill tool paths forming a laminate having a combined in-shell behavioramong two or more shells, further comprising solidifying the anisotropicfill material in fiber swaths tracking the set of complementaryanisotropic fill tool paths for at least the first sequence of parallelshells.

Alternatively, or in addition, the method may include solidifying theanisotropic fill material in fiber swaths tracking an inner concentricset of anisotropic fill tool paths for at least one of the first orsecond sequence of parallel shells, the inner concentric set ofanisotropic tool paths being located surrounding one or more negativecontours or through hole within the 3D printed part.

Further alternatively, or in addition, the method may includesolidifying the anisotropic fill material in fiber swaths tracking aninner concentric set of anisotropic fill tool paths for at least one ofthe first or second sequence of parallel shells, the inner concentricset of anisotropic tool paths being located looping an envelope shapeincluding at least two or more negative contours or through holes withinthe 3D printed part.

Optionally, or in addition, the anisotropic fill material may besolidified in fiber swaths tracking a cellular infill pattern ofanisotropic fill tool paths for at least one of the first or secondsequence of parallel shells, the cellular infill pattern of anisotropictool paths forming repeating and cellular walls of anisotropic fillmaterial within the 3D printed part.

Further optionally, the method may include solidifying the anisotropicfill material in fiber swaths tracking a self-crossing pattern ofanisotropic fill tool paths for at least one of the first or secondsequence of parallel shells, the self-crossing pattern of anisotropictool paths overlapping anisotropic solidification of fiber swaths withina same shell or layer.

In another embodiment, or embodiment of the invention, machineimplemented method for displaying a three-dimensional geometry of a partto be 3D printed on a display may include receiving thethree-dimensional geometry of a part to be 3D printed sliced into shellsor layers. The method may further include displaying the shells orlayers of the three-dimensional geometry of the part to be 3D printed ona display, and displaying, for a shell or layer, a representation of adistribution of a substantially isotropic fill material. For ananisotropic fill subset of the set of shells or layers, a representationmay be displayed of a distribution of a substantially anisotropic fillmaterial having an anisotropic characteristic oriented relative to atrajectory of an anisotropic fill tool path. A selection may bereceived, from among the displayed shells or layers defining the portionof the 3D printed part, of an editing subset of shells or layers, theediting subset including at least part of the anisotropic fill subset.For a shell or layer of the editing subset, one of a secondrepresentation of a distribution of isotropic fill material differentfrom the first representation of a distribution of isotropic fillmaterial and a second representation of a distribution of anisotropicfill material different from the first representation of a distributionof anisotropic fill material may be regenerated.

The method may include displaying an orthogonal bar together with thedisplayed shell, the orthogonal bar displayed parallel to an edge of thedisplay, the orthogonal bar including the representation of adistribution of a substantially isotropic fill material and therepresentation of a distribution of the substantially anisotropic fillmaterial.

Optionally, indicia may be displayed indicating the span of a firstgeneration rule common to a first range of shells or layers of thethree-dimensional geometry of the part to be 3D printed.

Alternatively, or in addition, in response to a predetermined conditionbeing met, the method may include ceasing to display at least one of,while continuing to display at least one remaining one of, therepresentation of the distribution of a substantially isotropic fillmaterial, the representation of the distribution of substantiallyanisotropic fill material, or the indicia indicating the span of thefirst generation rule common to the first range of shells or layers ofthe three-dimensional geometry of the part to be 3D printed.

Optionally, multiple indicia may be displayed indicating the extents ofa plurality of generation rules are displayed in a mutually exclusivemanner without overlapping; and/or the multiple indicia may be displayedadjustment handles indicating the extents of the plurality of generationrules.

Further optionally, the method may include detecting a movement of apointer in a direction relative to the display and/or an actuation ofthe pointer, and may include, in response to detecting the movementand/or the actuation of the pointer, changing the first generation rulecommon to the first range of shells or layers to a different, secondgeneration rule common to the first range of shells or layers.Alternatively, or in addition, in response to detecting the movementand/or the actuation of the pointer, displayed indicia indicating theextent of the first generation rule may be changed so that change in theextent of the first range is one of highlighted or displayed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a continuous core reinforced filamentdeposition and fill material filament extrusion printer.

FIG. 1B is a cross-sectional and schematic view of a compound extrusionand fiber printhead assembly.

FIG. 1C is a close-up cross-section of a fiber printhead assembly and aset of different possible compression/consolidation shapes.

FIG. 1D is a set of photographs of exemplary cross sections of extruded,non-compressed “FDM” or “FFF” depositions.

FIGS. 2A through 2C are schematic representations of a three dimensionalprinting system using a continuous core reinforced filament togetherwith stereolithography or selective laser sintering in which FIGS. 2Aand 2B are schematic views of a continuous core reinforcedfilament-SLA/SLS printer and FIG. 2C is a schematic view of a tackingprocess.

FIG. 2D is a schematic representation of a three dimensional printingsystem being used to form multiple layers in a printed circuit board.

FIG. 2E is a schematic representation of a rotatable printing nozzleincluding a following feeding and compression roller.

FIG. 2F is a schematic representation of a multi-nozzlethree-dimensional printer.

FIG. 2G is a schematic representation of a three dimensional printingsystem including a print arm (e.g., a robot arm having 4 or more degreesof freedom) and selectable printer heads.

FIG. 2H is a schematic representation of a multi-element printer headfor use in the printing system.

FIG. 3 is a block diagram and schematic representation of a threedimensional printer capable of printing with the compound printheadassembly of FIG. 1B.

FIG. 4 is a flow chart describing the overall operation of the 3Dprinter of FIG. 3.

FIG. 5A is a block diagram and schematic representation of a threedimensional printer system, including a CAD station, a slicer and pathgenerator, a region and path designer, and the three dimensionalprinter.

FIG. 5B shows an exemplary file or data structure format for recording astate of operation of prioritized or ordered rules and parameters forthe process of FIG. 8.

FIG. 6 is a call diagram depicting an exchange of data structures amongelements of the three dimensional printer system.

FIG. 7 is a flow chart describing the overall operation of the slicerand path generator of FIG. 4.

FIG. 8 is a flow chart describing the overall operation of a subcontouror region generator of FIG. 7.

FIG. 9A is a flow chart describing processing of global rules in FIG. 8.

FIG. 9B is a flow chart describing processing of path rules in FIG. 8.

FIG. 9C is a flow chart describing processing of region rules in FIG. 8.

FIG. 9D depicts a flowchart for configuring 3D printer controller and/orslicer controller operations to permit multi-layer rule handling, e.g.,setting rules for groups of layers or regions and changing the membersof the rule groups.

FIG. 10A shows an exemplary on-screen part rendering and logic structurefor the rule processing of FIG. 9A for global operations.

FIG. 10B shows an exemplary on-screen part rendering and logic structurefor the rule processing of FIG. 9B for layer operations.

FIG. 10C shows an exemplary on-screen part rendering and logic structurefor the region and/or rule processing of FIG. 9C.

FIG. 10D shows an exemplary on-screen part rendering and logic structurefor the region and/or rule processing of FIG. 9C, 9D.

FIG. 10E-10K shows an exemplary on-screen part rendering and logicstructure for the rule propagation procedure of FIG. 9D.

FIGS. 11A-11E show models, renderings, representations of toolpaths, anddata structures as carried out by the part rendering and logic structureof FIGS. 10A-10K, for a sandwich panel rule example, a crossovermovement example, and a region extrusion example;

FIGS. 11F-11G show schematic representations of a printed part includinga reinforced holes formed therein;

FIG. 11H shows exemplary composite layup via 3D printing of compositefibers as disclosed herein in contrasting directions;

FIGS. 12A-12J show composite swaths and/or path planning for layers oflinkage arms or base plates.

FIGS. 13A-13C show complementary paths for reinforcing a hole,distributed between 2, 3, or 4 layers.

FIGS. 14A-14C show the principles of complementary toolpaths in atrilaterally symmetric (three sided) context; FIGS. 14D-14E in a foursided context; and FIGS. 14G-14I in a second example of a three sidedcontext.

FIG. 15A shows a single layer of a densely filled square plate of fourlong side members, with a hole or negative contour in the middle.

In FIG. 15B, two superimposed reinforcement formations 99X, 99X layersare shown, where the reinforcement formation 99X is rotated by 90degrees, optionally in the subsequent layer.

Each of FIGS. 16A-16D shows reinforcement formations 99 within single ormultiple layers LA_(n), LA_(n+1), LA_(n+2), etc.

FIG. 17 is a schematic representation of a composite part formed usingthree-dimensional printing methods; and

FIG. 18 is a scanning electron microscope image of a reinforcing carbonfiber and perpendicularly arranged carbon nanotubes;

FIGS. 19A-19C show exemplary six-axis shell layup in contrastingdirections;

FIGS. 19D-19G show exemplary weighted distributions of 3D printedcomposite lay-up according to the present embodiments, e.g., to formsandwich panel structures, to increase effective moment of inertia;

FIGS. 19H-19J show exemplary weighted distributions of 3D printedcomposite lay-up according to the present embodiments, e.g., to formsandwich panel shell and fiber cellular interior structures, using bothquasi-isotropic sets of shells or layers and concentrically reinforcedshells or layers, to increase effective moment of inertia about theentire surface of the part as well as increase crushing and torsionalresistance;

FIG. 20 shows a composite swath 2 c of a reinforcement formation in alayer LA_(n) continuously deposited end-to-end with an adjacentreinforcement formation continuing into the next layer LA_(n+1), i.e.,without cutting the composite swath 2 c as the part 14 is indexed to thenext layer.

DETAILED DESCRIPTION

This patent application incorporates the following disclosures byreference in their entireties: U.S. Patent Application Ser. Nos.61/804,235; 61/815,531; 61/831,600; 61/847,113; 61/878,029; 61/880,129;61/881,946; 61/883,440; 61/902,256; 61/907,431; 62/080,890; Ser. Nos.14/222,318; 14/297,437; and Ser. No. 14/333,881, which may be referredto herein as “Composite Filament Fabrication patent applications” or“CFF patent applications”.

Definitions

In the present disclosure, “3D printer” is inclusive of both discreteprinters and/or toolhead accessories to manufacturing machinery whichcarry out an additive manufacturing sub-process within a larger process.With reference to FIGS. 1-5, 3D printer is controlled by a motioncontroller 20 which interprets dedicated G-code 1102 and drives variousactuators of the 3D printer in accordance with the G-code 1102.

As used herein, “extrusion” shall have its conventional meaning, e.g., aprocess in which a stock material is pressed through a die to take on aspecific shape of a lower cross-sectional area than the stock material.Fused Filament Fabrication (FFF) is an extrusion process. Similarly,“extrusion nozzle” shall have its conventional meaning, e.g., a devicedesigned to control the direction or characteristics of an extrusionfluid flow, especially to increase velocity and/or restrictcross-sectional area, as the fluid flow exits (or enters) an enclosedchamber. The present disclosure shall also use the coined word “conduitnozzle” or “nozzlet” to describe a terminal printing head, in whichunlike a FFF nozzle, there is no significant back pressure, oradditional velocity created in the printing material, and the crosssectional area of the printing material, including the matrix and theembedded fiber(s), remains substantially similar throughout the process(even as deposited in bonded ranks to the part). As used herein,“deposition head” shall include extrusion nozzles, conduit nozzles,and/or hybrid nozzles. Also as used herein, a reference to a Figurenumbers with no following letter suffix shall refer also to all lettersuffixes of the same Figure number, e.g., a reference to “FIG. 1” refersto all of FIGS. 1A, 1B, 1C, and 1D.

Lastly, in the three-dimensional printing art, “filament” typicallyrefers to the entire cross-sectional area of a spooled build material,while in the composites art, “filament” refers to individual fibers of,for example, carbon fiber (in which, for example, a “1K tow” will have1000 individual strands). For the purposes of the present disclosure,“filament” shall retain the meaning from three-dimensional printing, and“strand” shall mean individual fibers that are, for example, embedded ina matrix, together forming an entire composite “filament”.

3D Printing System

The printer(s) of FIGS. 1A-1C, with at least two print heads 18, 10and/or printing techniques, deposit with one head a fiber reinforcedcomposite filament, and with a remaining head apply pure or neat matrixresin 18 a (thermoplastic or curing). The fiber reinforced compositefilament 2 (also referred to herein as continuous core reinforcedfilament) may be substantially void free and include a polymer or resinthat coats, permeates or impregnates an internal continuous single coreor multistrand core. It should be noted that although the print head 18is shown as an extrusion print head, “fill material print head” 18 asused herein includes optical or UV curing, heat fusion or sintering, or“polyjet”, liquid, colloid, suspension or powder jetting devices (notshown) for depositing fill material.

Although FIGS. 1A-1C in general show a Cartesian arrangement forrelatively moving the print-heads in 3 orthogonal translationdirections, other arrangements are considered within the scope of, andexpressly described by, a drive system or drive or motorized drive thatmay relatively move a print head and a build plate supporting a 3Dprinted part in at least three degrees of freedom (i.e., in four or moredegrees of freedom as well). For example, for three degrees of freedom,a delta, parallel robot structure may use three parallelogram armsconnected to universal joints at the base, optionally to maintain anorientation of the print head (e.g., three motorized degrees of freedomamong the print head and build plate) or to change the orientation ofthe print head (e.g., four or higher degrees of freedom among the printhead and build plate). As another example, the print head may be mountedon a robotic arm having three, four, five, six, or higher degrees offreedom; and/or the build platform may rotate, translate in threedimensions, or be spun.

The fiber reinforced composite filament 2, 2 a is fed, dragged, and/orpulled through a conduit nozzle 10, 199 optionally heated to acontrolled temperature selected for the matrix material to maintain apredetermined viscosity, force of adhesion of bonded ranks, meltingproperties, and/or surface finish.

After the matrix material or polymer 4, 4 a is substantially melted, thecontinuous core reinforced filament 2 is applied onto a build platen 16to build successive layers 14 to form a three dimensional structure. Therelative position and/or orientation of the build platen 16 and conduitnozzle 10 are controlled by a controller 20 to deposit the continuouscore reinforced filament 2 in the desired location and direction.

A cutter 8 controlled by the controller 20 may cut the continuous corereinforced filament during the deposition process in order to (i) formseparate features and components on the structure as well as (ii)control the directionality or anisotropy of the deposited materialand/or bonded ranks in multiple sections and layers. At least onesecondary print head 18 may print fill material 18 a to form walls,infill, UV resistant and/or scratch resistant protective coatings,and/or removable, dissolvable, or soluble support material.

The supplied filament includes at least one axial fiber strand 6, 6 aextending within a matrix material 4, 4 a of the filament, for example anylon matrix 4 a that impregnates hundreds or thousands of continuouscarbon, aramid, glass, basalt, or UHMWPE fiber strands 6 a. The fiberstrand material has an ultimate tensile strength of greater than 300MPa.

The driven roller set 42, 40 push the unmelted filament 2 along aclearance fit zone that prevents buckling of filament 2. In a threadingor stitching process, the melted matrix material 6 a and the axial fiberstrands 4 a of the filament 2 are pressed into the part 14 and/or intothe swaths below 2 d, at times with axial compression. As the buildplaten 16 and print head(s) are translated with respect to one another,the end of the filament 2 contacts the ironing lip 726 and issubsequently continually ironed in a transverse pressure zone 3040 toform bonded ranks or composite swaths in the part 14.

FIG. 1B depicts a cross section of a compound (e.g., at least dual)print head with an extrusion printhead 1800 (as head 18) and extrusionnozzle 1802 for FFF and a fiber deposition printhead 199 (as head 10)and conduit nozzle 708 for continuous fiber reinforced thermoplasticdeposition. Like numbered features are similar to those described withrespect to FIG. 1A.

The feed rate (the tangential or linear speed of the drive 42, 40)and/or printing rate (e.g., the relative linear speed of the platen/partand print head) may be monitored or controlled to maintain compression,neutral tension, or positive tension within the unsupported zone as wellas primarily via axial compressive or tensile force within fiberstrand(s) 6 a extending along the filament 2.

As shown in FIGS. 1B and 1C, a transverse pressure zone 3040 includes anironing lip 726 that reshapes the filament 2. This ironing lip 726compacts or presses the filament 2 into the part and may also melt, heatto cross glass transition into a non-glassy state, and/or liquefy thematrix material 4 a in the transverse pressure zone 3040. Optionally,the ironing lip 726 in the transverse pressure zone 3040 flattens themelted filament 2 on the “top” side (i.e., the side opposite the part14), applying an ironing force to the melted matrix material 4 a and theaxial fiber strands 6 a as the filament 2 is deposited in bonded ranksor composite swaths 2 c. For example, the controller 20 maintains theheight of the bottom of the ironing lip 726 to the top of the layerbelow as less than the diameter of the filament (e.g., to compress to ½the height of the filament, at least at ½the filament height; tocompress to ⅓ the height of the filament, at least at ⅓ the filamentheight, and so on). The controller 20 may maintain the height at of thebottom of the ironing lip 726 to the layer below at zero (e.g., in whichcase the amount of consolidation/compression and the fiber swath 2 cheight may be a function of system stiffness). Another reshaping forceis applied as a normal reaction force from the platen 16 or part 14itself, which flattens the bonded ranks or composite swaths 2 c on atleast two sides as the melted matrix material 4 a and the axial fiberstrands 6 a are ironed to form laterally and vertically bonded ranks(i.e., the ironing also forces the bonded ranks 2 c into adjacentranks).

As shown in FIG. 1C, if the underlying layer or swaths 2 d includeschannels, the normal reaction force from the part 14 may create T-shapesinstead. The pressure and heat applied by ironing improves diffusion andfiber penetration into neighboring ranks or swaths (laterally andvertically).

As shown in FIG. 1B, unmelted fiber reinforced filament may be severedin a gap 62 between a guide tube 72 (having a clearance fit) and theconduit nozzle 708; or within the conduit nozzle 708, e.g., upstream ofthe non-contact zone 3030; and/or at the clearance fit zone 3010, 3020or at the ironing lip 726.

After the matrix material 6 a is melted by the ironing lip or tip 726,the feed and/or printing rate can be controlled by the controller 20 tomaintain neutral to positive tension in the composite filament 2 betweenthe ironing lip 726 and the part 14 primarily via tensile force withinthe fiber strands 4 a extending along the filament 2. A substantiallyconstant cross sectional area of the fiber reinforced composite filamentis maintained in the clearance fit zone, the unsupported zone, thetransverse pressure zone, and also as a bonded rank is attached to theworkpiece or part 14.

With reference to FIG. 1B, each of the printheads 1800 and 199 may bemounted on the same linear guide or different linear guides or actuatorssuch that the X, Y motorized mechanism of the printer moves them inunison. As shown, the FFF printhead 1800 includes an extrusion nozzle1802 with melt zone or melt reservoir 1804, a heater 1806, a highthermal gradient zone 1808 formed by a thermal resistor or spacer 1809(optionally an air gap), and a Teflon or PTFE tube 1811. A 1.75-1.8 mm;3 mm; or larger or smaller thermoplastic filament is driven through,e.g., direct drive or a Bowden tube provides extrusion back pressure inthe melt reservoir 1804.

The companion continuous fiber embedded filament printhead 199, asshown, includes the conduit nozzle 708, the composite ironing tip 728,and the limited contact cavity 714, in this example each within aheating block heated by a heater 715. A cold feed zone 712 may be formedwithin a receiving tube 64, including a capillary-like receiving tube ofrigid material and a small diameter (e.g. inner diameter of 32 thou)Teflon/PTFE tube extending into the nozzle 708. The cold feed zone issurrounded in this case by an insulating block 66 a and a heat sink 66b, but these are fully optional. In operation, an unattached terminalend of the fiber-embedded filament may be held in the cold feed zone,e.g., at height P1. Height P1, as well as cutter-to-tip distance R1, areretained in a database for permitting the controller 20 to thread andadvance the fiber-embedded filament as discussed herein. If P1 and R1are very similar (e.g., if the cutter location is near or within thecold feed zone), P1 may be set to be the same or similar to R1. Furtheras shown, the controller 20 is operatively connected to the cutter 8,8A, and feed rollers 42 facing idle rollers 40.

FIG. 1C shows a schematic close-up cross section of the conduit nozzle708. As shown in FIG. 1C, the inner diameter of the receiving tube 64(in this case, at a position where a Teflon/PTFE inner tube forms theinner diameter) may be approximately 1½ to 2½ times (at, e.g., 32 thou)the diameter of the filament 2 (at, e.g., 12-15, or 13 thou) showntherewithin. The inner diameter or inner width of the terminal cavity714 (at, e.g., 40 thou) is from two to six times the diameter of thefilament 2 shown therein. These are preferred ranges, it is consideredthe diameter of the receiving tube may be from 1 1/10 to 3 times thediameter of the filament, and the inner diameter of the terminal cavityfrom two to 12 times the diameter of the filament. The terminal cavityis preferably of larger diameter than the receiving tube.

In addition, as shown in FIG. 1C, the heated composite filament ironingtip 726 is moved relative to the part, at a height above the part ofless than the filament diameter and scaled according to a desiredproportion of composite swath, to iron the fiber reinforced compositefilament 2 as it is deposited to reshape a substantially oval orcircular bundle of inelastic axial fiber strands 6 a within the fiberreinforced composite filament to a substantially flattened block ofinelastic fibers strands within a bonded rank 2 c of the part. Axialcompression and/or laterally pressing the melted matrix filament 2 intobonded ranks may enhance final part properties. For example, FIG. 1Cshows a composite fiber reinforced filament 2 applied with a compactionforce, axial compression, or lateral pressure 62. The compactionpressure from axial compression and flattening from the ironing lip,compresses or reshapes the substantially circular cross-section filament2 a into the preceding layer below and into a second, substantiallyrectangular cross-section compacted shape 2 c. The entire filament 2 aforms a bonded rank 2 c (i.e., bonded to the layer below 2 d andprevious ranks on the same layer) as it is shaped.

The filament 2 c and/or interior strands 6 a of the filament 2 c bothspread and intrude into adjacent bonded ranks 2 c or 2 d on the samelayer and the matrix material 4 a and strands 6 a are compressed intothe underlying shaped filament or bonded rank of material 2 d. Thispressing, compaction, or diffusion of shaped filaments or bonded ranks 2c, 2 d reduces the distance between reinforcing fibers, and increasesthe strength of the resultant part (and replaces techniques achieved incomposite lay-up using post-processing with pressure plates or vacuumbagging). Accordingly, in some embodiments or aspect of the inventiondiscussed herein, the axial compression of the filament 2 and/orespecially the physical pressing by the printer head 70, conduit nozzleor ironing lip 726 in zone 3040 may be used to apply acompression/compaction/consolidation pressure directly to the depositedmaterial or bonded ranks or composite swaths 2 c to force them to spreador compact or flatten into the ranks beside and/or below.Cross-sectional area is substantially or identically maintained.

Alternatively or in addition, pressure may be applied through a trailingpressure plate behind the print head; a full width pressure plate and/orroller 2138 (see, e.g., FIG. 2E) spanning the entire part that appliescompaction pressure to an entire layer at a time; and/or heat, pressure,or vacuum may be applied during printing, after each layer, or to thepart as a whole to reflow the resin in the layer and achieve the desiredamount of compaction (forcing of walls together and reduction andelimination of voids) within the final part.

FIGS. 2A-2H depict embodiments of a three dimensional printer inapplying a fiber reinforced composite filament 2 together with DLP-SLA,SLA, SLS, “polyjet” or other techniques to build a structure. Likenumbered or like appearance features may be similar to those describedwith respect to FIG. 1A.

Although one embodiment or aspect of the invention uses thermoplasticmatrix, hybrid systems are possible. A reinforced filament may employ amatrix that is finished by a curing cycle, e.g., using heat, light,lasers, and/or radiation. For example, continuous carbon fibers areembedded in a partially cured epoxy such that the extruded componentsticks together, but requires a post-cure to fully harden. Similarly,while one embodiment or aspect of the invention use preformed continuouscore reinforced filaments, in some embodiments, the continuous corereinforced filament may be formed by combining a resin matrix and asolid continuous core in a heated extrusion nozzle. The resin matrix andthe solid continuous core are able to be combined without the formationof voids along the interface due to the ease with which the resin wetsthe continuous perimeter of the solid core as compared to the multipleinterfaces in a multistrand core. Therefore, such an embodiment may beof particular use where it is desirable to alter the properties of thedeposited material.

FIGS. 2A and 2B depict a hybrid system employing stereolithography(and/or selective laser sintering) to provide the matrix about theembedded fiber, i.e. processes in which a continuous resin in liquid orpowder form is solidified layer by layer by sweeping a focused radiationcuring or melting beam (laser, UV) in desired layer configurations. Inorder to provide increased strength as well as the functionalitiesassociated with different types of continuous core filaments includingboth solid and multistrand materials, the stereolithography processassociated with the deposition of each layer can be modified into atwo-step process that enables construction of composite componentsincluding continuous core filaments in desired locations and directions.A continuous core or fiber may be deposited in a desired location anddirection within a layer to be printed, either completely or partiallysubmerged in the resin. After the continuous fiber is deposited in thedesired location and direction, the adjoining resin is cured to hardenaround the fiber. This may either be done as the continuous fiber isdeposited, or it may be done after the continuous fiber has beendeposited. In one embodiment, the entire layer is printed with a singlecontinuous fiber without the need to cut the continuous fiber. In otherembodiments, reinforcing fibers may be provided in different sections ofthe printed layer with different orientations. In order to facilitatedepositing the continuous fiber in multiple locations and directions,the continuous fiber may be terminated using a cutter as describedherein, or by the laser that is used to harden the resin.

FIG. 2B depicts a part 1600 being built on a platen 1602 usingstereolithography or selective layer sintering. The part 1600 isimmersed in a liquid resin (photopolymer) material or powder bed 1604contained in a tray 1606. During formation of the part 1600, the platen1602 is moved by a layer thickness to sequentially lower after theformation of each layer to keep the part 1600 submerged. During theformation of each layer, a continuous core filament 1608 is fed througha conduit nozzle 1610 and deposited onto the part 1600. The conduitnozzle 1610 is controlled to deposit the continuous core filament 1608in a desired location as well as a desired direction within the layerbeing formed. The feed rate of the continuous core filament 1608 may beequal to the speed of the conduit nozzle 1610 to avoid disturbing thealready deposited continuous core filaments. As the continuous corefilament 1608 is deposited, appropriate electromagnetic radiation (e.g.,laser 1612) cures or sinters the resin surrounding the continuous corefilament 1608 in a location 1614 behind the path of travel of theconduit nozzle 1610. The distance between the location 1614 and theconduit nozzle 1610 may be selected to allow the continuous corefilament to be completely submerged within the liquid resin or powderprior to curing. The laser is generated by a source 1616 and is directedby a controllable mirror 1618. The three dimensional printer alsoincludes a cutter 1620 to enable the termination of the continuous corefilament as noted above.

Optionally, the deposited filament is held in place by one or more“tacks”, which are a sufficient amount of hardened resin material thatholds the continuous core filament in position while additional corematerial is deposited. As depicted in FIG. 2C, the continuous corefilament 1608 is tacked in place at multiple discrete points 1622 by thelaser 1612 as the continuous core filament is deposited by a nozzle, notdepicted. After depositing a portion, or all, of the continuous corefilament 1608, the laser 1612 is directed along a predetermined patternto cure the liquid resin material 1604 and form the current layer.Similar to the above system, appropriate electromagnetic radiation(e.g., laser 1612), is generated by a source 1616 and directed by acontrollable mirror 1618. The balance of the material can be cured tomaximize cross linking between adjacent strands is maximized, e.g., whena sufficient number of strands has been deposited onto a layer andtacked in place, the resin may be cured in beads that are perpendicularto the direction of the deposited strands of continuous core filament.Curing the resin in a direction perpendicular to the deposited strandsmay provide increased bonding between adjacent strands to improve thepart strength in a direction perpendicular to the direction of thedeposited strands of continuous core filament. If separate portions ofthe layer include strands of continuous core filament oriented indifferent directions, the cure pattern may include lines that areperpendicular or parallel to the direction of the strands of continuousfibers core material in each portion of the layer.

FIG. 2D depicts printing of a multi-layer PCB 1800, on a build platen16. The PCB 1800 is formed with a conductive core material 1802 and aninsulating material 1804 which are deposited using a printer headincluding a heated extrusion nozzle 10 and cutting mechanism 8. Similarto the multielement printer head, the conductive core material 1802 andinsulating material 1804 may be selectively deposited eitherindividually or together. Further, in some embodiments the conductivecore material 1802 is solid to minimize the formation of voids in thedeposited composite material. When the conductive core material 1802 isprinted without the insulating material 1804 a void 1806 can be formedto enable the subsequent formation of vias for use in connectingmultiple layers within the PCB 1800. Depending on the desiredapplication, the void 1806 may or may not be associated with one or moretraces made from the conductive core material 1802.

When desirable, a precision roller set can be used to maintain aconstant thickness along a relatively wider width of material outputfrom a print head 2102. Such an embodiment may be of use when dealingwith wider materials such as flat towpregs. FIG. 2E shows a print head2102 translating in a first direction. A nozzle 2136 of the print headis attached to a trailing compression roller 2138. The roller 2138imparts a compressive force to the material deposited onto print bed2140. Depending on the embodiment, the trailing roller 2138 canarticulate around the Z axis using any number of different mechanisms.For example, in one embodiment, the print head 2102 is free-rotating ona bearing (e.g., adding a fourth degree of freedom), such that theroller always trails the direction of travel of the print head. Inanother embodiment, the entire print head 402 is constructed to rotate(e.g., adding a fourth degree of freedom). Alternatively or in addition,the print bed 2140 may be rotated (e.g., as a fourth or fifth degree offreedom) to achieve the desired trailing and displacement.

FIG. 2F shows one embodiment of a high-speed continuous core printercapable of using the above described materials. In the depictedembodiment, the printer includes a print arm 2200 including a pluralityof nozzles. The nozzles include a pure resin nozzle 2202 adapted toprint pure resin (e.g., as fill material) 2208. The print arm 2200 alsoincludes a continuous core filament nozzle 2204 adapted to print acontinuous core filament 2210 for use in fine detail work. Additionally,the print arm 2200 includes a tape dispensing head 2206 capable ofprinting one or more printable tapes 2212. The tape dispensing headenables large infill sections to be printed quickly using the notedprintable tapes. However, fine detail work and gaps that cannot befilled in by the tape can be filled by either the pure resin nozzle 2202or continuous core filament nozzle 2204. The above noted method andsystem using wide tape fills greatly improves the speed of a printer,enabling higher throughput, and commensurately lower cost.

In FIG. 2G, an (e.g., robot arm) print arm 1400 is capable of attachingto printer head 1402 at a universal connection 1404. A continuous corereinforced filament 1406 may be fed into the printer head 1402 before orafter attachment to the printer 1400. The print arm 1400 may return theprinter head 1402 to an associated holder or turret and then pick upprinter head 1408 or 1410 for printing filament and other consumablesdifferent in size, material, color, coating, and/or spray; or even avision system 1412 (e.g., camera, rangefinder) for part inspection.

The continuous core reinforced filament may be formed by adding a resinmatrix or coating to a solid continuous core or a prepreg in a heatedconduit or extrusion nozzle. FIG. 2H depicts a multi-element printerhead 1500 that selectively combines (in any feasible combination) andextrudes material feed options core 1502 (e.g., continuous copper wire,continuous fiber, stranded prepreg wire or fiber), matrix 1504 (e.g.,binding resin such as nylon), and support 1506 (e.g., a dissolvablesupport material). For example, a core 1502 might be surrounded by amatrix binder 1504 on the bottom surface and a dissolvable/solublesupport 1506 on the top surface (e.g., section 1508). The multi-elementprinter head 1500 may also deposit the core 1502 coated with either thematrix binder 1504 or soluble support 1506 separately (e.g., sections1510 and 1514), or e.g., deposit any of the materials individually(e.g., the bare core or copper wire at section 1512).

As shown in FIG. 2H, multi-element printer head 1500 (or any other printhead embodiment depicted herein) may include an air nozzle 1508 whichenables pre-heating of the print area and/or rapid cooling of theextruded material to aid in forming structures such as flying leads, gapbridging, and other similar features. For example, a conductive corematerial may be deposited by the multi-element printer head 1500 with aco-extruded insulating plastic, to form a trace in the printed part. Theend of the trace may then be terminated as a flying lead (themulti-element printer head lifts and deposits the core and jacket),optionally cooling the insulating jacket with the air nozzle 1508. Theend of the wire could then be printed as a “stripped wire” where theconductive core is extruded without the insulating jacket. The cuttingmechanism 8 may then terminate the conductive core. Formation of aflying, uninsulated lead in the above-noted manner may be used toeliminate a later stripping step.

FIG. 3 depicts a block diagram and control system of the threedimensional printer which controls the mechanisms, sensors, andactuators therein, and executes instructions to perform the controlprofiles depicted in and processes described herein. A printer isdepicted in schematic form to show possible configurations of, forexample, three commanded motors 116, 118, and 120. It should be notedthat this printer may include the compound assembly of printheads 199,1800 depicted in FIG. 1C.

As depicted in FIG. 3, the three-dimensional printer 3001 includes acontroller 20 which is operatively connected to the fiber head heater715, the fiber filament drive 42 and the plurality of actuators 116,118, 120, wherein the controller 20 executes instructions which causethe filament drive to deposit and/or compress fiber into the part. Theinstructions are held in flash memory and executed in RAM (not shown;the instructions may be embedded in the controller 20). An actuator 114for applying a spray coat, as discussed herein, may also be connected tothe controller 20. In addition to the fiber drive 42, a filament feed1830 be controlled by the controller to supply the extrusion printhead1800. A printhead board 110, optionally mounted on the compoundprinthead 199, 1800 and moving therewith and connected to the maincontroller 20 via ribbon cable, breaks out certain inputs and outputs.The temperature of the ironing tip 726 may be monitored by thecontroller 20 by a thermistor or thermocouple 102; and the temperatureof the heater block holding nozzle 1802 of any companion extrusionprinthead 1800 may be measured by a thermistor or thermocouple 1832. Aheater 715 for heating the ironing tip 726 and a heater 1806 for heatingthe extrusion nozzle 1802 are controlled by the controller 20. A heatsink fan 106 and a part fan 108, each for cooling, may be shared betweenthe printheads 199, 1800 and controlled by the controller 20.Rangefinder 15 is also monitored by the controller 20. The cutter 8actuator, which may be a servomotor, a solenoid, or equivalent, is alsooperatively connected. A lifter motor for lifting one or eitherprinthead 199, 1800 away from the part (e.g., to control dripping) mayalso be controlled. Limit switches 112 for detecting when the actuators116, 118, 120 have reached the end of their proper travel range are alsomonitored by the controller 20.

As depicted in FIG. 3, an additional breakout board 122, which mayinclude a separate microcontroller, provides user interface andconnectivity to the controller 20. An 802.11 Wi-Fi transceiver connectsthe controller to a local wireless network and to the Internet at largeand sends and receives remote inputs, commands, and control parameters.A touch screen display panel 128 provides user feedback and acceptsinputs, commands, and control parameters from the user. Flash memory 126and RAM 130 store programs and active instructions for the userinterface microcontroller and the controller 20.

FIG. 4 depicts a flowchart showing a printing operation of the printers1000 in FIGS. 1-3. FIG. 4 describes, as a coupled functionality, controlroutines that may be carried out to alternately and in combination usethe co-mounted FFF extrusion head 1800 and fiber reinforced filamentprinting head 199 of FIG. 1C.

In FIG. 4, at the initiation of printing, the controller 20 determinesin step S10 whether the next segment to be printed is a fiber segment ornot, and routes the process to S12 in the case of a fiber filamentsegment to be printed and to step S14 in the case of other segments,including e.g., base, fill, or coatings. Step S12 is described in detailwith reference to FIGS. 2 and 12. After each or either of routines S12and S14 have completed a segment, the routine of FIG. 4 checks for slicecompletion at step S16, and if segments remain within the slice,increments to the next planned segment and continues the determinationand printing of fiber segments and/or non-fiber segments at step S18.Similarly, after slice completion at step S16, if slices remain at stepS20, the routine increments at step S22 to the next planned slice andcontinues the determination and printing of fiber segments and/ornon-fiber segments. “Segment” as used herein corresponds to “toolpath”and “trajectory”, and means a linear row, road, or rank having abeginning and an end, which may be open or closed, a line, a loop,curved, straight, etc. A segment begins when a printhead begins acontinuous deposit of material, and terminates when the printhead stopsdepositing. A “slice” is a single layer or lamina to be printed in the3D printer, and a slice may include one segment, many segments, latticefill of cells, different materials, and/or a combination offiber-embedded filament segments and pure polymer segments. A “part”includes a plurality of slices to build up the part. The control routineshown by way of example in FIG. 4 permits dual-mode printing with twodifferent printheads, including the compound printheads 199, 1800 ofFIG. 1C, and using both timing approaches of FIG. 6.

FIGS. 5A and 5B depicts a block diagram of a three dimensional printersystem, including devices in the system and relevant databases, datastructures, control messages, and file formats which cooperate tocontrol the printers of FIGS. 1-3 and as described throughout. FIG. 6depicts a call diagram in which data types and operations are relatedand communicated between devices.

As shown in FIGS. 5A, 5B and 6, in order to construct a part using a 3Dprinter 1000, the process usually begins with a solid modelcorresponding to a part (“PRT”) of interest represented by a datastructure (“files” 802, having a drawing container DWG with assemblies“ASSY” comprising various parts “PRT”), but may also begin with apolygon mesh of the desired part (STL 902 in FIG. 3). As shown in FIGS.5 and 6, the solid model may be represented by non-uniform rationalb-spline NURBS data, and this may be stored and processed by a CADprogram on a workstation, server, or virtualized/cloud server 2000, andcommunicated by file or data structure to a meshing program on the sameor a different workstation, server, or virtualized/cloud server 2000.One of the data structures most amenable to division into layers foradditive manufacturing is the surface mesh of cells or polygons havingedges, faces and vertices stored as a geometry file (e.g., an STL, OBJ,PLY, AMF or WRL file). As used herein, “geometry file” and/or “STL” 902are used generically and interchangeably to mean data structures(including groups of files) inclusive of both surface meshes and CADsolid model representations that use techniques other than surfacemeshing (e.g., a “NURBS” definition).

In preparation for 3D printing, a geometry file is “sliced” by a familyof slicer routines 904 (as shown in FIGS. 5 and 6, resident on aworkstation, server, or virtualized/cloud server) in a directionparallel to the expected build platen to create a series of layers orlamina (“Empty Deck” 906). Geometry files are usually without materialdefinition, and each individual lamina would be initially treated as ofhomogenous or isotropic material properties. Alternatively, oneembodiment of a geometry file 902 may include markers, boundaries,sub-geometries, divisions, boundary conditions, or the like specifying adifferent material property according to volumetric location within thegeometry file.

Subsequently, for each layer, toolpaths (“layers and slices” 1002) arecalculated by a path planner 1004 for controlling actuators to deposit,focus a laser or lamp or projector to cure, solidify, or otherwise applymaterial. As shown in FIGS. 5 and 6, the toolpath generator is alsoresident on a workstation, server, or virtualized/cloud server. In thepresent discussion, “toolpath” encompasses both moving a tool throughspace and pure electromagnetic paths (e.g., optical, radiation) “moved”with mirrors and lenses. Toolpaths may be arranged within contours,which may subdivide a layer perimeter into areas of different attention,e.g., where a larger or smaller deposition head is necessary to reachsome part of the lamina geometry, or to observe rule sets 1006 fordifferent parts of the layer (e.g., walls, interior perimeter, fills).Toolpaths are generated per internal algorithms that determine offsets,scales, and cellular decomposition for complete coverage approaches ofthe various contours. Some parameter control may be applied to the rules1006 (e.g., an adjustable 1-5 thicknesses of deposited plastic for anouter perimeter forming rule).

An FFF toolpath may have variables including extrusion width (relatingto the nozzle size, nozzle height from build surface, and extrusionspeed). Other deposition toolpaths in additive manufacturing may havevariables similarly relevant to the physics and chemistry of theindividual process.

As shown in FIGS. 5 and 6, a customizer routine 2008 (permitting one orboth of automated and manual editing) may permit changes to thegenerated toolpaths, regions or subcontours, contours, layers, and mesh.Some customizations may require merely re-pathing, others may create newregions, others may create new geometry model sections—these changes maybe done as they are entered by a user, or may be batched and redone.Optionally, after all customizations are done, the process is returnedto the earliest practical phase with all changes protected to bere-meshed, re-sliced, or re-pathed.

As sent to the 3D printer 2000, the toolpaths are used to create aninstruction file for actuation, conventionally called a “G-code” file orstream 1102. The toolpath generator 2006 generates toolpaths and mayalso serve as the G-code generator 2010 by interpreting the toolpathsinto a machine-specific code. The G-code is sequenced including allstarting and finishing times, control or command variables (e.g., speedfor a motor, current for a heater), and the like, to arrange theactuator instructions sufficient for a job to complete. The G-code 1002file, because it is dependent upon physical arrangement of the printeritself, is typically printer specific.

This process—slicing, then generating toolpaths, then generatingG-code—whether used for conventional additive or subtractivemanufacturing, may or may not include any provision for, the uniquecharacteristics of embedded and/or reinforcing continuous orsemi-continuous fiber—i.e. anisotropic characteristics including stress,strain, thermal conductivity, load and support direction specificdesign, or the like.

FIGS. 5A, 5B and 6, for the purpose of reference terms throughout, showa series of steps in the data structure, each of which is optionallycombined with an adjacent step. As shown in FIGS. 5A, 5B and 6, areference part as stored in a CAD geometry file includes a definition ofexterior walls, upward facing “floors” and downward facing “ceilings”,interior “roofs”, interior through-holes, and interior “solid” spaces.

As shown in FIGS. 5A, 5B and 6, when converted into an STL, the 3D datastructure is transformed into a geometry mesh defining only the exteriorperimeter, but retains all of the characteristics of the more complexCAD representation. As noted, this is optional, as the meshrepresentation is easier to “slice”. Defective, non-“watertight” ornon-manifold STLs may be repaired such that all vertices are properlyconnected, but the representation as a mesh remains essentially similar.

As shown in FIGS. 5A, 5B and 6, “slicing” the STL includes twoconceptual steps, which are often done together. First, at each heightincrement, a cross-section must be taken through the STL parallel to theanticipated build platen orientation. Second, necessary toolpaths areexpressed as G-code for a deposition head to deposit material along theexterior and interior perimeters of the slice and also to create anyinterior structures (such as fills). The toolpaths and G-code may begenerated at each slicing operation, such that these steps are merged.For the purpose of this discussion, “slicing” will be discussed as a setof merged steps in which cross-sectional slices are taken and pathplanning and G-code are generated for uniform material fill.

As shown in FIGS. 5A, 5B and 6, slicing operations identify and usetoolpaths to surround exterior and interior lateral walls (e.g.,optionally 1-3 fused polymer rows at each); fill interior volumes withdense, packed, sparse, cellular or lattice structures; form ceilings,floors, and roofs optionally with slower print speeds; and createtemporary, removable or soluble support structures used during the printcycle. In addition, toolpaths for moving tools from origin to printstart to print stop, and for feeding and retracting filament to startand stop extrusion, are created.

Customizations may be associated with a layer and recorded in arule/parameter database e.g., as a toolpath with trajectory data.Additionally or in the alternative, with reference to FIG. 10B, theregions created by the change (a changed concentric fiber region R08, aswell as a yet smaller interior region R10) may be recorded in a file ordatabase as regions protected versus global operations as well as layeroperations and region operations.

As noted above, arrangements are considered within the scope of, andexpressly described by, a drive system or drive or motorized drive thatmay relatively move a print head and a build plate supporting a 3Dprinted part in at least three degrees of freedom (i.e., in four or moredegrees of freedom as well), such as a delta robot or robot arm drivepermitting four or higher degrees of freedom among the print head andbuild plate. Accordingly, as used herein, “layers” and “shells”deposited by the print head(s) or deposition head(s) or solidificationhead(s) may mean any layer or stratum or shell that may be formed inthree degrees of freedom or higher (i.e., in four or more degrees offreedom as well), as appropriate, which may be planar layers in the caseof three translation degrees of freedom (although shallowly curvedlayers may be formed even with three translation degrees of freedom), orcurved, cupped, convex, concave, or topologically or topographicallycomplex layers, shells, or layers or shells following two dimensionalmanifolds (and/or “sliced” in such shapes). Although the Figures andexamples herein often show planar layers or shells, the presentdescription and claims expressly contemplate that a layer or shell maybe curved (and/or “sliced” in such curved shapes), and the orientationof print head(s), deposition head(s) or solidification head(s) drivensuch that such head(s) are normal or near-normal to the surface beingprinted and tracking along such surface in 3D space, or otherwiseappropriately oriented to deposit the layer or surface.

FIG. 7 is a flow chart describing the overall operation of path planner,i.e., the slice, contour, subcontour (region) and path generator andplanners depicted in FIGS. 5 and 6. The fiber path planner of FIG. 7receives as an input a “sliced” database of layers from the slicer. Thissliced stack database may be in the form of, per layer, topologicalinformation (contours, defined as a solid or a hole via the conventionalright hand rule), and/or toolpath information (trajectories), metadata,and/or G-code or an equivalent. For example, one form of subset wouldinclude the “SLC” file format or an equivalent, which includes only thegeometry of the contours. A superset could include the STL file, oranalyses or parameters recognized from the STL file (e.g., a label for athrough hole that is shared by code segments generating that throughhole in G-Code).

It is a distinction from either or both of conventional additivemanufacturing and conventional subtractive manufacturing that the fiberpath planner may work with individual layers or slices, but also with afew, several, or many at a time.

It should be noted that the initial input for a first pass on a 3D partto be printed, where no layer-by-layer fiber path generation has yetbeen performed that could be repathed, the “slices and contours”discussed herein. It is an optional object of the present disclosure tosubsequently deal with re-pathing on a database of layers rather thanwith the 3D model geometry, to thereby only repath those contours andthose layers that should be changed. However, the present disclosurefurther contemplates that in some situations, repathing from an earlierstage may be beneficial (e.g., for Boolean and/or parametric operationssupported at the region level, in addition to or in the alternative toat the layered level).

It should be noted that the process of creating toolpaths for ordinaryadditive manufacturing may not conventionally require repathing, nor maybe comparison to any but one or two adjacent layers conventionallynecessary. In toolpaths generated for depositing fill material only,toolpaths/G-code are built up from a platen assumption; material is notextruded in the same location twice; and the tool need not be moved backin the Z direction opposite to the direction of build, even for the caseof multi-material or multi-part STLs. Should changes need to be made,the process of generating new tool-paths is generally to redo the partin CAD, create a new STL, and reslice/repath the entire geometry file(STL).

However, in order to edit the interior structure of the part to beprinted, including the placement for fiber, at least some repeatedoperation in toolpath generation is preferred, to accommodate manual ornew automatic changes in fiber placement performed by the path planner,or to provide the freedom of designing reinforcing fiber within a partdesigned on a CAD system with no provision for anisotropic materials.

Accordingly, as noted below, the process of FIG. 7 can be entered withits own output, i.e., the process of FIG. 7 is intended to analyze andchange both data sets having only layers and contours, as well as the“slices, contours, regions, and toolpaths” set generated by the toolpathgenerator and modified in customization, and there are cases in which itmay be beneficial to do so (e.g., in case incremental processes areinterdependent).

In step S750, the process, in a mesh pre-processing step, corrects theSTL file for various errors, including at least one of: correcting facenormal orientation; self-intersections; non-manifold geometry andmanifold errors; vertices not incident to any edge; edges without anyincident triangles; edges with more than two incident triangles;vertices with a non-disc neighborhood; disconnected, or unwantedhandles, tunnels, components, or cavities; erroneous holes or cavities;triangles with near-zero or zero area. Techniques include mergingvertices within a prescribed distance; merging or stitching adjacentboundary edges; clipping then merging overlapping patches; hole fillingby inserting vertices; and converting mesh into point cloud andremeshing. This step may generate a simplified, more robust, mesh inwhich each vertex and edge is uniquely defined, and faces are generatedfrom defined vertices and edges.

In step 752, the process slices the (pre-processed or corrected)geometry (e.g., triangle) mesh in to layers, strata, or slices (theseterms used interchangeably). Techniques include checking all trianglesor groups of proximate triangles vs. all cutting planes forintersections; checking all edges vs. all cutting planes forintersections (sweep plane slicing); or checking all planes forintersections with intervals representative of each triangle. Thisgenerates a set of two dimensional slices at a fixed height or variableheight (either may be recorded as metadata for a particular slice). Thefixed or variable height may be of any thickness/resolution printable bythe target 3D printer, e.g., 0.02″, 0.01″, 0.005″, 0.001″, 0.1 mm andmultiples of these, or even of a lesser thickness/resolution useful forinter or intra-layer insertions. Each slice includes at least onepositive contour (e.g., an outer perimeter) and may include one or morenegative contours (e.g., a hole or holes). A positive contour may alsocreate a proxy for a hole, e.g., by specifying a perimeter that loops totouch (e.g., meld with) itself to create such hole proxies(s).

In step S754, the process inventories the state of default rules for FFFand fiber printing selected for automated contours and toolpaths, andsets an order of operations for the default rules selected. An exemplarystate of such rules are shown in FIGS. 8 and 9A and described withreference thereto. The order of operation of rules may be linear,recursive, or otherwise arranged. A predetermined overall order ofoperations may interrelate all possible operations. It should be notedthat a change in rules (e.g., changing or adding or subtracting a rule)any time during the process may, by interrupt, trigger, commit orotherwise, restart the process at step S755 (entry point “A”) toaccommodate the change. The user may be afforded an opportunity tomodify these default rules before the first execution of step S756(e.g., skip to step S760).

It should be noted that the creation of internal contours or regions forthe operation of a particular rule or application of a particularinternal design structure within can take place before, after, or duringthe operation of the rule or design. Some rules are more amenable todefining a boundary as they operate (e.g., contour-following fills);other rules are more amenable to working with a certain perimeter (e.g.,patterned fills such as honeycomb or triangle); still other rules aremore amenable to including a required bounding contour as part of theirdefinition (e.g., hole-reinforcing patterns, insert-reinforcingpatterns).

In step S756, the process applies the ruleset, layer by layer, accordingto the order of operations, to determine sub-contours, i.e., twodimensional topological sub-areas and/or holes within a positivecontour, as new dependent positive and/or negative contours. Again,negative contours may form holes, or positive contours may form proxiesfor holes. In addition, positive contours may be created by ruleset totrigger or force a desired pathing or filling of fiber or material.Sub-contours may have perimeters coincident with an enclosing orneighboring contour, and a positive sub-contour may form a wall of ahole in the layer). FIGS. 8 and 9A-9C include further detail onsub-contour generation.

In step S758, the process applies the ruleset, contour by contour,according to the order of operations, to generate desired toolpaths forfilling of fiber or material, as well as transitions therebetween, forone or more fiber laying tools and for one or more material depositiontools. When all paths are generated, the initial printing strategy iscomplete. At this point the toolpaths may be translated to G-code andthe part may be printed, and an end-user may be offered the opportunityto review and/or print the toolpath state or the part (e.g., at thebeginning of the customization process).

As discussed herein, a segment, toolpath or path is a sequence oftrajectories and contours. A trajectory is a connected sequence of pathcommands. Toolpath commands may include line segments and partialelliptical arcs, and optionally Bezier curve segments. Each path commandmay have path coordinates, and a pair of path coordinates may be an X, Ylocation that is a control point. A contour is a closed trajectory withthe same start and end point. Toolpaths are executed (e.g., by adeposition printhead, by laser or UV curing, by flash DLP curing) orrendered (e.g., to display upon a review panel) by “stroking” the path.In the case of a toolhead, the “stroking” may be depositing material orcuring material as swept out by a fixed-width deposition centered on thetrajectory that travels along the trajectory orthogonal to thetrajectory's tangent direction. Stroking may be by area or accumulated(an entire area may be flashed by DLP as a toolpath).

With respect to offsetting of or contours toolpaths discussed herein,parallel or offset toolpaths may be created using offset generation fornon-Bezier base paths and offset stroking for Bezier (e.g., cubic orquadratic control point) base paths. Optionally, because offset strokingfor Bezier paths may be difficult to render, FFF material or fiber pathsmay be non-Bezier approximations. Resolution-independent path renderingmay be performed by via vector graphic libraries for GPU acceleratedpath rendering (e.g., OpenVG) even to calculate toolpaths and offsets ofphysical continuous fiber paths.

In step S760, the process permits the customization, layer by layer,contour by contour, and/or path by path, of the completed toolpath andprinting strategy. The customization process is optional, as is eachtype of customization.

As shown in FIGS. 8 and 9A-9C, subcontours (or “regions”) and in somecases toolpaths are generated layer by layer in a priority or order ofprecedence. Global rules are optionally of lowest precedence, as theyare most likely to be overridden by direct user changes (actual designdecisions) or indirect user changes (results of design decisions).

The process of FIG. 8 is carried out both initially and in later editingstages. In an initial pass, no user changes of fiber paths orregions/subcontours will have been recorded, so there will be no useredited fiber paths or subcontours to process at highest priority. Inthis initial pass, the highest priority may be global rules.

Within and among each set of processed rules, higher priority rules,once defining a toolpath and/or region, are generally protected as thenext, lower priority set of rules are processed. In the case of aconflict, the user may be given a warning and opportunity to elevate thepriority of a nominally lower priority rule. The priority stack may alsobe considered an order of operations. Higher priority actions areoptionally not disturbed by later actions unless a failure mode rule isbroken.

While the actual order of priorities may be dependent uponimplementation, in one implementation, the general order of rules is:failure mode rules (e.g., limits of the platen or of the tool heads, ofunsupported spans of a particular material, etc.); toolpath rules; thensubcontour rules; then layer rules; then global rules. In each step,direct edits are or were preferably only permitted in a manner whichdoes not violate (optional) failure mode rules (e.g., another failuremode rule may be that an unsupported spans of isotropic fill materialcan extend, e.g., no more than 1 cm in length, or other length specifiedas a property of the material).

In step S850 initially, in any layer in which a toolpath was edited, anymanual or automated operation in which a toolpath is or was directlyedited by a user is processed by first plotting the related toolpath(and any dependencies) and then defining the envelope which the toolpathoccupies, protecting the envelope as a region or subcontour. An exampletoolpath edit operation is changing the position of control points orwaypoints of a curve defining a toolpath.

In optionally subsequent step S852, among all the layers, the regions orsubcontours protected in step S850 are now “off limits”. Manual orheuristic operations in which a subcontour is or was directly edited bya user are processed by protecting the region or subcontour. Toolpathsmay be generated at a later time. An example subcontour edit operationis specifying a void volume (e.g., an solid model to be overmolded) thatextends through several layers.

In optionally subsequent step S854, layer rules (i.e., rules that havebeen set for an entire layer) are processed. Regions or subcontoursprotected in prior steps are now “off limits”. Manual or heuristicoperations in which a layer is or was directly edited by a user areprocessed by protecting all remaining regions or subcontours in thelayer. Toolpaths may be generated at a later time. An example layer editoperation is specifying that fiber fill will be used on a particularlayer that had not by toolpath, subcontour or global rules otherwisebeen defined as a fiber layer.

In step S856, global rules (i.e., rules that have been set for theentire part) are processed. Typical global rules are shown in a prioritystack in FIG. 8C, e.g., with wall thicknesses of highest priority andinfill of lowest priority. Some or all global rules may optionally oralternatively take precedence over other rules.

FIG. 9A is a flow chart in which different types of global rule areexecuted. As noted, although FIG. 9A may take place after the otherroutines of the slicing and path planning process (or at lowerpriority), the user may be presented with the results of FIG. 9A'sprocessing of default and global rules before any customizations aremade or processes. As noted, a later path, region, layer, or volumecustomization that deposits fiber or other second material at a wall,floor, roof, fiber fill region, exception fill region, or area fillregion may optionally (e.g., set by a parameter) override the globalwall thickness setting; and each successive toolpaths generation definesregions in each layer which are nominally protected vs. later toolpathgeneration.

In step S8560, the process of FIG. 9A refers to database settings forwall thicknesses and generates toolpaths corresponding to the walls ofthe part. Walls may be the perimeters of contours, subcontours, orregions. A typical global setting may be from 2-4 bonded ranks; innerwalls (holes) and outer walls (shells) may have different global ordefault settings.

In step S8562, the routine generates “roofs” and “floors” according to aset parameter (e.g., independently settable at a default 3 layers of anyof 1-5 layers, or as a thickness for variable thickness layers). A roofis an external surface facing “up” (i.e., the direction in which layersare built), a floor is an external surface facing “down” (opposite toup).

In step S8562, the routine generates fiber fills according to globalrules discussed herein with respect to FIGS. 10 through 11C.

FIG. 9B is a flow chart in which different types of path rule areexecuted. As noted, direct editing toolpaths, or heuristic oralgorithmic determination of toolpaths, takes precedence in oneembodiment. As noted, a path customization that deposits fiber orpolymer at a wall, floor, roof, fiber fill region, exception fillregion, or area fill region may optionally override the global, layer,or regional rules or settings.

In step S8502, the process of FIG. 9B refers to any recorded directedits (again, which may be manual or automated operations) that wererecorded, and generates the corresponding toolpaths, protecting theregion surrounding those toolpaths from region, layer, or globaloperations. The discussion of FIG. 13 below will describe exemplarydirect edits.

In step S8504, groups of crossovers (e.g., “crossover” includingS-shaped-bends switching a fiber path from one offset to an adjacentoffset, L-shaped-bends switching a fiber path from one direction to atransverse direction, and/or U-shaped-bends or folds switching a fiberpath from one direction to a substantially opposite but paralleldirection) in the same directed to be shifted, or required to be shiftedby operation of heuristic or other rule, are shifted. In this context,as shown in FIG. 11D, the crossover toolpaths L22 (TP06, TP08, TP10) are“shifted” by—even were they placed by global rule in a defaultposition—staggered or relatively migrated about the track of theconcentric band. In this manner, stress concentration and/or slightreduction in tensile strength is distributed among layers, rather thanstacked up among layers.

In step S8504, groups of crossovers directed to be shifted, or requiredto be shifted by operation of heuristic or other rule, are shifted. Inthis context, as shown in FIG. 11D, the crossover toolpaths L22 (TP06,TP08, TP10) are “shifted” by being staggered or relatively migratedabout the track of the concentric band. In this manner, stressconcentration and/or slight reduction in tensile strength is distributedamong layers, rather than stacked up among layers. As a layer operation,the shifting of crossovers may override crossovers placed by global rulein a default or enabling position (e.g., as shown in FIG. 10C atlocation TP0, in a location that permits the continuous fiber to remainan uncut track).

In step S8504 of FIG. 9B, groups of crossovers directed to be placed oncurves, or required to be placed on curves by operation of heuristic orother rule, are so pathed. In this context, as shown in FIG. 11D, thecrossover toolpaths L22 (TP06, TP08, TP10) are located on a curve ratherthan on a straight section. In general, straight sections may beintended to bear tension or compression load, and placement ofcrossovers on a curve, minimizes the stress concentration and nominallylower strength along the fiber. As shown in FIG. 11D, the curve connectsthe straightaways and may be a superior location for the crossovers. Theplacement of crossovers on curves is by example a path operation, butmay be a global, layer or region operation.

FIG. 9C is a flow chart in which different types of region rule areexecuted. In one embodiment, direct editing toolpaths, or heuristic oralgorithmic determination of toolpaths, takes precedence over the regionrules. In step S8524, the process of FIG. 9C refers to any recordeddirect region edits (again, which may be manual or automated operations)that were recorded, and generates the corresponding toolpaths,protecting the region surrounding those toolpaths from layer or globaloperations.

FIG. 9D depicts a flowchart for configuring 3D printer controller and/orslicer controller operations to permit multi-layer rule handling, i.e.,setting rules for groups of layers or regions and changing the membersof the rule groups. In step S7602, updating or re-slicing of toolpathsfrom any toolpath, region, or layer setting change is carried out. Instep S7604, as necessary, any changes in the currently displayedgraphical representation resulting from an updated toolpath (e.g.,change of a layer, group of layers, or volume) are processed anddisplayed. In step S7606, as shown in FIGS. 10E-10I, graphicalrepresentations of rule groups and end points of the rule groups arerendered as orthogonal bar(s) parallel to an edge of a display. In stepS7610, the display area of the orthogonal bar is monitored for a pointerPO1 action selecting, an entire group, an endpoint of a group, or a newrange within and/or adjacent an existing group, and the input handledaccording to the particular case.

When an entire group is selected and retaining focus, in step S7613, oneor more interface elements (e.g., a drop down menu, slider, text ornumber box, radio button, check box or other user interface controltype) are monitored for input reflecting a change in the rule applied tothe selected entire group, and the rule change is captured from theinput. When an endpoint of a group (e.g., a group will have at least twoendpoints, but may have any number for non-contiguous groups) isselected per step S7614 and retains focus, in step S7618 one or moreinterface elements (e.g., a drop down menu, slider, text or number box,radio button, check box) are monitored for input reflecting a change inthe position of the endpoint, and therefore a change in the members inthe set of layers or regions of the group, and the rule change iscaptured from the input. When a new range is formed or is selected perstep S7612 and retains focus, in step S7616 one or more interfaceelements (e.g., a drop down menu, slider, text or number box, radiobutton, check box) are monitored for input reflecting a change in therule applied to the selected entire group, and the rule change iscaptured from the input and the new group created in step S7620. If thenew group is within a previously existing group, three new groups may becreated (e.g., the new group selected as well as one or two fractionalremainder groups reflecting that part of the previously existing groupwhich was not changed). In each case, in step S7622, the rule change isapplied and the process proceeds back to step S7602 to update thetoolpaths per the rule change or range change, as well as the graphicalrepresentation (7604) and representation on the orthogonal bar (S7606).

As shown in FIG. 10A, at the global level, the user may choose to “usefiber” as a parameter P02, where a “use” (automatic) setting permitsglobal, path, layer, and region fiber reinforcement, a “no fiber”setting suppresses all fiber reinforcement, and a “custom” settingpermits only path, layer, or region determined fiber reinforcement. Theuser may specify a parameter P06 as a number of immediately adjacentfiber layers, and a parameter P08 as a number of immediately adjacentfiber shells or ranks, for global fiber operations (which optionallybecomes the initial setting for any path, layer, or regions setting).The user may set a parameter P04 as a type of fiber (e.g., carbon fiber,aramid fiber, or fiberglass).

The exemplary model M01 shown in FIG. 10A to receive the operations ofthe rulesets and ultimately to be printed is a connecting rod includinga torque transmitting feature F02 including a polygonal hole/splinesurrounded by a large reinforcing circular mount, a slip fit feature F04including a cylindrical through hole surrounded by a smaller reinforcingcircular mount, and an arm feature F06 spanning the two features F02 andF06. “Spanning” herein means extending beyond the lateral or lengthwiseextent of one or two features, e.g., a span length F08 extends past theedges of the hole features F02 and F04, is longer than the outeredge-to-edge length.

Detail settings that may be set at a global level also include (i) aparameter for false/dense/lean migrate or stagger for sets of fibercrossovers, which for adjacent layers moves the location of a group ofcrossovers between adjacent offsets so that crossovers are concentratedin zones or spread out as desired; (ii) a parameter forcurves/straightaways for the preferred location of fiber crossovers; or(iii) a parameter for higher or lower moment of inertia, to concentratefiber to the perimeters or center of a part.

FIG. 10A shows an exemplary on-screen part rendering and logic structurefor the rule processing of FIGS. 8 and 9A-9C. A view panel 1002 includesan on-screen rendering of a geometry file retained in memory or otherdatabase. The geometry file rendered in the view panel 1002 may be shownin different views (e.g., isometric, perspective, orthogonal), and/or indifferent sections, and/or with or without layers, contours, regions ortoolpaths rendered within. Examples include an isometric model shown inFIG. 10A or 10K; an exploded view of layers shown in FIG. 11A, a “layerat a time” plan view with a layer number control slider shown in FIGS.10B-10I, 11B and 11C. In each view, occluded toolpaths or surfaces maybe hidden or shown, and rendered lines and surfaces may be rendered withselective color and transparency as set by the user. Contour, region,layer, fill, material, and other metadata corresponding to acharacteristic may be rendered in outline and/or highlighted withselective color and transparency as set by the user.

A selection panel 1004 includes a set of user interface elements thatcorrespond to command flags, arrays, and lists stored in memory or otherdatabase (e.g., as shown in FIG. 5B). As disclosed herein, whether ornot particularly disclosed separately in discussion of data structures,each on-screen rendering corresponds to that data structure discussedherein necessary to render the view, and each view panel and selectionpanel user interface element corresponds to a respective flag, array, orlist retained in a database in like form to those particularly detailed.

Exemplary global rules that control path planning for each layer thatare available to the path planner, and also available to a displayrenderer for the view panel and a controls renderer for the selectionpanel, are shown in the view panel 1004. Numbering for features renderedin the view panel 1004 may reference any of FIGS. 10A-10I (display,interface), FIG. 8 or 9A-9D (process control), FIGS. 5A, 5B (rule setsand data structures), as each are related as the data structuresdefining operations and the part are created and changed by processcontrol according to rule sets and priorities, and the results of thechanges displayed to the user. Several available choices are notdepicted in FIG. 10A, although these would appear in an available viewpanel. For example, the user may select (and the path planner therebyexecute) the thickness of and/or number of bonded ranks forming innerand/or outer walls or shells, the thickness and/or number of bondedlayers for floors and/or roof dense or watertight fills; whether or notto use peelable and/or soluble supports for printing overhangs; and/or afill pattern (triangle, hex, square, cellular) for infill of inner areasfor weight reduction. Generally, many more parameters may be set bypresenting a configuration file (e.g., layer thickness and/or bonded rowwidth; variable feedrate for curves, bends, or outer/inner walls;bridging (printing unsupported spans) lengths for neat plastic or fiber;or limitations for printing spurs (single walled sections).

FIG. 10B shows an exemplary display for layer rule operations on a viewpanel 1002, and is again generated by rendering to screen 2D definitions(optionally presented in 3D) of contours, subcontours, and toolpaths,with optional processing for occlusion and showing and hiding particularfeature types. An alternative plan view per layer is shown in the viewpanel 1002, set to the sixth layer (of an exemplary approximately 200layers). An end user may optionally return to another view (e.g.,semi-transparent isometric), but retain the same controls and layernumber slider P01.

As an example, a scenario is carried out in FIG. 10B in the per-layerediting method (a combination of pathing customization step S760, whichpresents different interfaces for implementation of rules, and ruleprocessing and region protection step S854, which processes and protectsuser changes on a layer by layer basis). A user wishes to directlygenerate a structure similar to that of FIG. 19F by doubling the amountof fiber reinforcement in an outermost layer, or at least in a layerdistant from the centroid, to improve the effective moment of inertia.If roofs and floors are set to be a low number of layers, e.g., five asin FIG. 11A, and the roof and floor global setting is protected versususer edits, then the target layers for direct editing of globallyautomated operations be in this example layers 6 and 101.

As shown in FIG. 10B, for layer 6 the user has specified 6 fiber shellsinstead of the 3 fiber shells consistent with the global rules, andmoreover has turned off “sparse infill”. Accordingly, three additionaloffsets are generated, and fiber pathed (toolpath TP04B) to follow thoseoffsets and rendered to screen. With reference to FIG. 20, thesecustomizations may be associated with layer 6 and recorded in arule/parameter database as shown, e.g., “Layer 6—Concentric Rings 6—FillPattern off”. Additionally or in the alternative, with reference to FIG.21, the regions created by the change (a larger concentric fiber regionR08, as well as a smaller interior region R10, now no longer to besparsely filled) may be recorded in a file or database as protectedversus global operations, i.e., protected subcontours. Note, in thepresent embodiment, the layer change is not protected versus region orpath change by the user.

Additionally as shown in FIG. 10B, the last two offsets generated forfiber fill no longer loop about the hole and interior negative contours.This operation generates a potential exception fill, as well as apotential stress concentration in the fiber cusps on the inboard side ofthe negative contour. While a smoothing operation may be applied as aglobal rule, or as a layer rule that may be set per layer, to remove thecusp and/or stress concentration, for the purpose of this disclosure thecusps will be used as an example for user editing of paths and/orregions. FIG. 10C shows an exemplary on-screen part rendering and logicstructure for the rule processing of FIG. 9B. Parameters for crossovermigration or placement are not shown, but could be available in thisstructure. The view panel 1002 includes an on-screen rendering of atarget layer of the geometry file retained in memory or other database.The selection panel 1004 includes a set of user interface elements thatcorrespond to command flags, arrays, and lists stored in memory or otherdatabase (e.g., as shown in FIG. 5B).

Exemplary tools and rules that control path planning for the currentlayer are available to the path planner, to a display renderer for theview panel 1002 and to a controls renderer for the selection panel 1004,are as shown in the view panel 1004. Numbering for features rendered inthe view panel 1004 may reference any of 10A-10I (display, interface),FIG. 8 or 9A-9D (process control), FIGS. 5A, 5B (rule sets and datastructures), each inter-related as the data structures defining theoperations and the part are created and changed by process controlaccording to rule sets and priorities, and the results of the changesdisplayed to the user.

As shown in FIG. 10C, at the pathing level, the user may choose a subsetof the same changes available at the layer level (e.g., the number ofshells or the pathing strategy). A set of direct editing tools areavailable, and the implementation thereof via mouse or touch driveninterface connected to record selections and move graphical indiciarepresentative of screen location would be understood by one of ordinaryskill in the art. A lock for editing permits the user some protectionfrom inadvertent edits, although an undo function is operative for FIG.10C and would also help. The toolset includes (i) a fiber selectioncursor, for choosing one or more entire trajectories, segments, ortoolpaths; (ii) control point selection, addition, and deletion cursor,for selecting, moving, adding, and deleting control points of fibertrajectories/toolpaths rendered in FIG. 10C as NURBS or Bezier curves;(iii) segment joining and splitting cursors, for combining and splittingtoolpaths (especially should heuristic or algorithmic path generation atthe global, layer, or regional level be an obstacle to the designer'sintent); (iv) a move crossover cursor, for selecting and moving a groupof related (i.e., adjacent to one another in parallel offsets)crossovers, e.g., along the track or to a curved portion of the track asdiscussed herein; and (v) an add new offset cursor, which will generatea new offset from a selected trajectory or toolpath, and fill the offsetwith a reinforced fiber toolpath (adding a crossover as necessary).

Again, as with FIG. 10B, an example scenario is carried out in FIG. 10Cin the per-path editing method, a combination of pathing customizationstep S760, which presents the interface of FIG. 10C for theimplementation of toolpath-level rules, and rule processing and regionprotection step S850, which processes and protects user changes on atoolpath-by-toolpath basis). A user wishes to directly remove the cuspsgenerated in the explanation of FIG. 10B, continuing the design intentto implement a structure similar to that of FIG. 19F.

As shown in FIG. 10C, for layer 6 the user has used the control pointcursor to select the innermost fiber loop, and has already deletedcontrol points to render a semicircle instead of the cusps. This edit iscomplete. As shown, the user has used the control point cursor toactivate a ghost loop having NURBS or Bezier control points, and hasplotted a curved, lesser stress path (outlined as a dual line ghostpath). Upon execution of this design, the new toolpaths are recorded andprotected versus coarser changes. Accordingly, one complex fibertoolpath is repathed (toolpath TP04B) to follow the new path and berendered or stroked display.

Accordingly, the operation of the toolpath level rule set, in the formof executable code or parameters controlling parameterized executablecode, permits semi-automated toolpath customizations. As noted, althoughthe toolpath rule set is in one embodiment of higher priority overregion, layer or global customizations, this priority may be otherwisearranged.

FIG. 10D shows an exemplary on-screen part rendering and logic structurefor the rule processing of FIG. 9C. Parameters for global or layer fillrules applicable to regions are not shown, but could be available inthis structure. The view panel 1002 includes an on-screen rendering of atarget layer and target regions of the geometry file retained in memoryor other database. The selection panel 1004 includes a set of userinterface elements that correspond to command flags, arrays, and listsstored in memory or other database (e.g., as shown in FIGS. 20 and/or21).

Exemplary tools and rules that control region generation and planningfor the current layer and current regions are available to the pathplanner, to a display renderer for the view panel 1002 and to a controlsrenderer for the selection panel 1004, are as shown in the view panel1004. Numbering for features rendered in the view panel 1004 mayreference any of 10A-10I (display, interface), FIG. 8 or 9A-9D (processcontrol), FIGS. 5A, 5B (rule sets and data structures), eachinter-related as the data structures defining the operations and thepart are created and changed by process control according to rule setsand priorities, and the results of the changes displayed to the user.

At the region level, the user may choose a subset of the same changesavailable at the layer level (e.g., the number of shells or the pathingstrategy), although this is not shown in FIG. 10D. A set of directediting tools are available, as with FIG. 10C the implementation thereofvia mouse or touch driven interface as understood by one of ordinaryskill in the art, with a functionally similar lock for editing and anundo function. The toolset includes (i) a region selection cursor, forchoosing one or more entire regions; (ii) control point selection,addition, and deletion cursor, for selecting, moving, adding, anddeleting control points of region contours rendered in FIG. 10D as NURBSor Bezier curves; (iii) Boolean region joining and splitting operators,for combining and splitting regions selected with the selection cursor(again, especially should heuristic or algorithmic region generation atthe global, layer, or regional level be an obstacle to the designer'sintent); (iv) a conform to neighbor operator, for incrementallyexpanding a region boundary to fully conform to neighboring regions, toavoid, e.g., gaps, overlaps, non-watertight, and/or non-manifold errorsin creation of regions; (v) a make offset shape operator, for creating anew region that is an offset of an existing region (a dialog may ask howwide the offset should be); (vi) a convert to hole operator, forconverting a region into a negative contour; (vii) a convert to solidoperator, for converting a region into a solid and/or positive contour;(viii) an extrude operator, for replicating a region up or down aspecified number of layers, inclusive; and (vii) a shape primitiveoperator, for creating primitive shapes that may be combined with oneanother or with existing regions using the Boolean region tools.

Toolpath appearance has been hidden in FIG. 10D for the sake ofexplanation and visibility of regions, but operation of the regiondirect editing tools would include the ability to show or hide toolpathswithin the regions, regenerate such toolpaths, select new toolpath rules(e.g., change the fill type of a region). For example, upon creation ofa shape, solid, or a Boolean operation between dissimilar filled shapes,the user would be required to specify a fill (solid, sparse infill, orfiber infill; of whatever type).

The extrusion operator, as a region level tool, takes precedence overlayer and global rules, but not over paths. In other words, a regionextruded from a present layer in the region editing mode will “punchthrough” global or layer defaults, but will not “punch through” auser-tuned toolpath. While shown with a range slider control from −100to +100 layers from the present layer, the extrusion operator wouldpermit extrusion to all layers (as with all slider controls disclosedherein, by direct entry or otherwise, e.g., by continuing to incrementor decrement at the end of the slider range). One example use of theextrusion tool is to extend a particular fiber toolpath design orcomplex sparse in-fill region internally within the part. Another is tocreate a new solid feature or hole. For example, a solid infill (bydefault) hexagon shape may be created with the shape tool, placed in adesired position according to its displayed size and location fromcontours of the part (e.g., “show dimensions” toggle “on” or measureablewith a measuring tool), extruded through the part, then punched throughwith the convert to hole operator. It should be noted that automaticallycreated regions can be, of course, operated on in the region editingwindow. For example, a protected boundary region created by a customizedtoolpath design using the toolset and rules of FIG. 10C would beavailable for editing, replication, or extrusion in the end-userinterface of FIG. 10D or otherwise to programmatic operation. In suchcases, where a higher priority toolpath-surrounding, toolpath-generated,and/or toolpath level protected region is edited, the end-user mayreceive a dialog or other warning and authorize editing, extruding, orreplicating of the protected toolpath-region.

In FIG. 10D, as with FIGS. 10B and 10C, in a per-region editing method,a combination of pathing customization step S760, which presents theinterface of FIG. 10D for the implementation of region-level rules, andrule processing and region protection step S852, which processes andprotects user changes on a region-by-region basis. In this scenario, theuser wishes to designate and propagate a small area as an exceptionalfill.

As shown in FIG. 10D, for layer 6 the user may use the select regioncursor to select two small remainder regions R12, which absentalgorithmic detection or user intervention will be filled with the samearea infill of region R10A. In the described scenario, remainder regionsR12 were created as cutouts from the expansion and subsequent manualrerouting of carbon concentric fill, creating and modifying region R08A.After selecting both regions R12 (e.g., with conventional mouse or touchmulti-object selection techniques), the user may extrude them up anddown to the extent they will fill in poorly with area fill, then convertto solid, where upon the user will be given a choice of fill—and wouldselect either solid fill or a dense fill for such exceptions.Accordingly, the exceptional regions would be printed with solid fillrather than a poor infill. In this particular case, the user's edit ofregion content changes the automatic area infill such that torquetransmitting feature F02 is reinforced along two polygonal sides totransmit force through solid polymer to the concentric fiber fillsurrounding it.

FIG. 10E-10I shows an exemplary on-screen part rendering and logicstructure for the rule propagation procedure of FIG. 9D. The view panel1002 may be the same or similar as in FIGS. 10A-10D, and includes anon-screen rendering of the geometry file retained in memory or otherdatabase, which may be shown in different views, as previouslydescribed. In the interest of focusing description on the features ofthe rule propagation procedure and interface, the selection panel 1004is not shown, but a selection panel 1004 in FIGS. 10E-10K would often beassociated with the view panel 1002 of FIGS. 10E-10K during rulepropagation operations, e.g., to show detailed rule descriptions and/orannotations descriptive of rules being propagated, as discussed, eachrule and user interface element corresponding to a respective flag,array, or list.

As discussed in FIG. 9D, rule propagation or rule “extrusion” permitsusers to define one or more rule formulations for one or more layers,and selectively propagate the rule(s) to other layers (or limit thelayer range of a pre-existing rule propagation). Rules may be propagatedon a per-region or per-layer basis, and may be propagated in acontinuous, recurring, interval-based or regular fashion. In oneembodiment, rules are adjacent and propagated in an exclusive fashion (alayer may have only one rule per region or per rule), and in anotherembodiment rules are overlapping and propagated in a priority basedfashion (a layer or region may have inconsistent rule definitions, butthese are prioritized in the same or similar fashion as is shown in FIG.8, e.g., (custom rules>default rules, path rules>region rules>customlayer rules>global rules). These embodiments are not mutually exclusiveand may be combined.

As shown in FIG. 10E and set forth in FIG. 9D, a database of rules asdepicted in FIG. 5B may be represented as an orthogonal slider or trackbar OB1.1 having integrated representations for current index location(e.g., thumb TH1), rule propagation extent (e.g., area rule sectionsRS1-RS4 and/or rule adjustment handles HA1-HA5 as grouping indicators),and optionally for fiber fill amount (e.g., fiber volume fill graphsections VFG1, VFG2). Associated with the orthogonal bar OB1.1 areannotations reflecting the current index location among the layers AN1,the extent of the currently selected dataset or graphic elementrepresenting the rule to be propagated AN2, and the selectable orchangeable rule selection interface element IE1. As shown in FIG. 10E, apointer PO1 (which may be a mouse pointer for a mouse based system or atracked finger location for a touch based system) is used to manipulatethe interface elements of the display shown in FIG. 10E and theirassociated data sets in a database as in FIG. 5B.

In particular, FIG. 10E shows an orthogonal layer topography bar OB 1.1extending across a lower part of the display 1002, representing four (4)rule sets extending across approximately 150 layers. The orthogonallayer topography bar 1.1 includes the first through fourth rule sectionsRS1-RS4 extending from layer 1-59, layer 60-88, layer 88-140, and layer141-150. As shown by the position of the thumb TH1, the currentlydisplayed layer is layer 72 within rule section RS1, within which layers1-35 include approximately 50% fiber fill as shown by the volume fillgraph section VFG1, but the current layer includes no fiber fill (asreflected by the displayed layer L10.1 or L10.2). Rule section RS2 isselected via pointer PO1, and is highlighted between rule adjustmenthandles HA2 and HA3, with annotation AN1 indicating that the commonrange of the rule of the selected rule section is layers 60 through 88,and annotation AN2 indicating that the rule selectable is a “NO FIBER”rule (from among fiber fill types, with the selectable rule itself beingchanged, e.g., via the selection panel 1004). “NO FIBER”, “CONCENTRICFILL”, and “ISOTROPIC FILL” (i.e., a recurring or repeating grouping oftwo to six adjacent layers with distributed rotations of boustrophedonfills, each group creating a quasi-isotropic multi-layer wafer) areavailable. “ISOTROPIC FILL” as noted herein is commonly known as“quasi-isotropic”, and approaches “isotropic” reinforcement whenmultiple anisotropic layers in with different dominant directions arecombined in a laminate, such that the laminate's extensional stiffnessmatrix behaves substantially like an isotropic material. In the presentdescription, a quasi-isotropic laminate pattern of 2-6 layers ofcomposite deposition may be repeatedly printed in immediately adjacentlaminate pattern stacks, in wafer-like stacks separated by plastic, insandwich panels, or in other patterns (e.g., logarithmic or otherprogressive distribution).

Rule 10F shows the step S7608, S7613 of FIG. 9D, in which the pointerPO1 has been used with the interface element IE1, a drop-down list inthis case, to select rule “CONCENTRIC FILL” to apply to selected layers60 through 88. After the rule is applied to each of layers 60 through 88and any necessary recalculations applied, the fiber volume meteringgraph updates to show approximately 20% as a newly appearing volume fillor metering graph section VFG3. The current layer “Layer 72” displayedas a graphical, 2D representation updates to show the now-changed fiberfill (from NO FILL to CONCENTRIC FILL) as three concentric fill loops(e.g., three loops, optionally set pursuant to a corresponding settingor parameter adjustable in the selection panel 1004).

FIG. 10G shows the step S7614, S7618 of FIG. 9D, in which the pointerPO1 has been used with the rule adjustment handle AH3 to alter the endpoint of the CONCENTRIC FILL rule from layer 88 as shown in FIG. 10Gdown to layer 75. The highlighting of the rule section RS2 is updatedfor the smaller extent, the extent of the volume fill graph is updatedto reflect this application of a CONCENTRIC FILL rule only applies fromlayer 60 to layer 75, and the 2D depiction of layer 72 at the currentindex position remains the same. In an equivalent manner, were ruleadjustment handle AH3 moved to the right to enlarge the size of the rulesection RS2 and raise the end point, the corresponding display elementsupdate to reflect the change.

FIG. 10H shows the step S7612, S7616, S7620 of FIG. 9D, in which thepointer PO1 has been used following FIG. 10F instead of (not necessarilyin addition to) the step shown in FIG. 10G. As shown, the pointer hasdefined and selected new range RS5 within the rule section RS2, and therule has been changed for this new range RS5 to “NO FIBER”, splittingformer rule section RS2 into new sections RS2-1 and RS2-2. Thehighlighting of the rule section RS5 is updated, the extent of thevolume fill graph within rule section RS5 is updated to reflect theapplication of a NO FIBER rule only from layer 68 to layer 75, and the2D depiction of layer 72 at the current index position is updated toreflect the NO FIBER change.

FIGS. 10I and 10J show an alternative embodiment of the orthogonal layertopography bar OB 1.2 a-OB1.2 c, an alternative approach to theorthogonal layer topography bar OB 1.1 of FIG. 10E. As shown anddescribed, like elements throughout the figures are often like numbered,but some numbers may be omitted in these views. The description ofelements of substantially identical appearance in other drawingsgenerally applies to FIGS. 10I and 10J, including the describedassociations among displays, processes, and databases. The orthogonallayer topography bar OB 1.1 of FIG. 10E is described in the context ofexclusive rule sections RS1-RS4 (although it may be used withnon-exclusive rule sections), FIGS. 10I and 10J are described in acontext of rule sections RS7-RS9 which may overlap. As shown in FIGS.10I and 10J, the orthogonal layer topography bar OB1.2 is formed as aset of independent orthogonal subbars OB1.2 a/RS7 through OB1.2 c/RS9,each subbar OB1.2 a through 1.2 c or rule section RS7 through RS9 beingassociated with adjustment handles at each end of each section.

As shown in FIG. 10I, extending across a lower part of the display 1002,the volume fill graph section VFG-B display element is a topographyrepresentation of approximately 150 layers, the same as or similar tothe volume fill graphs of FIGS. 10E-10H. As shown by the position of thethumb TH1, the currently displayed layer is layer 6 within rule sectionRS9, within which layers 4-44 and 107-147 include approximately 25%fiber fill as shown by the volume fill graph section VFG4, VFG5. Asshown, rule section RS9 is non-contiguous in two parts, i.e., thedisplay, interface, and database may record and apply customized ordefault rules (toolpath, region, or layer) to non-contiguous butassociated ranges of toolpaths, regions, or layers. Rule section RS9 isselected via pointer PO1, and is highlighted between rule adjustmenthandles HA9 and HA10, and again between handles HA11 and HA12, withannotation AN2 indicating that the common ranges of the rule of theselected rule section is layers 4-44 and 107-147, and annotation AN3indicating that the rule selectable for an associated “Volume 1” (e.g.,a volume formed by the height of the layers 4-44 and 107-147 and eitheran entire layer or a region within a layer) is a “CONCENTRIC FILL” rule(from among fiber fill types, with the selectable rule itself beingchanged, e.g., via the selection panel 1004). Reflecting the currentindex layer, the depicted model shows concentric fill of about 25percent fiber content in layer 6 within the rule ranges.

FIG. 10J shows a set of changes from the state of FIG. 10I of thedisplay state as well as corresponding processes and databases. Inparticular, FIG. 10J shows the addition of two additional rule sectionsRS8 and RS7 to the displays, processes, and databases. Rule set RS8, forexample, is a rule applicable from layer 3 to 150, in this case, forexample, a rule prescribing the concentric, inner negative contourfollowing hole wall reinforcement pattern HR, surrounding thethrough-hole W04 which passes through the part in each layer. Rule setRS7, for example, is a rule applicable in layers 35 through 70 and 100through 125, in which isotropic fill is prescribed for a particulardefined region or volume, or for example for any area which is nototherwise subject to a higher priority rule (not that the priority ofthe rules could be adjusted, e.g., by restacking (rearranging) the rulelayers RS7, RS8, RS9 such that the priority order is the order of thestack). As shown in FIG. 10J, the position of the thumb TH1 is shiftedto layer 61. The currently displayed layer is layer 50 spanning rulesections RS7, RS8, and RS9, within which the displayed layers includesthe 25% volume outer perimeter following concentric fill of rule RS9,the 10% volume circular negative contour perimeter following concentricfill of rule RS8, and the 75%+ volume isotropic fill IF, at this level a45 degree boustrophedon fill, of rule RS7. As noted, an isotropic fillIF will have a different angle depending on the level (e.g., rotatingamong 0, +45, −45, and 90 degrees to form repeating quasi-isotropicwafers). As shown by the volume fill graph section VFG6, the 10%, 25%,and 75% volume fill are additive on layers where rules overlap,indicating the simultaneous operation of the rules. Interface elementIE1 is selected via pointer PO1, and is shown in a configuration inwhich the layers indicated by annotation AN2, i.e., layers 35-70 and100-125, may have a common rule selected for them, in this caseisotropic fill. Similarly to the FIG. 10J, annotation AN2 indicates thatthe rule is selectable for an associated “Volume 3” (e.g., a volumeformed by the height of the layers 35-70 and 100-125, and either anentire layer or a region within a layer) is an “ISOTROPIC FILL” rule(from among fiber fill types, with the selectable rule itself beingchanged, e.g., via the selection panel 1004).

In the case where rules may “overlap” per layer, this may occur in atleast two forms. First, within a layer, different regions may haveindependent rules (e.g., as shown in FIG. 10J, each of threeregions—outer perimeter of three fiber rings, hole reinforcement ofthree fiber rings, and boustrophedon fill of the remainder—may bedefined by region). Second, for any path, region, layer, or volume,rules may take precedence by a predetermined priority. As described withreference to FIG. 8, one possible priority for rule category precedenceis toolpath rules being of highest priority, followed by region rules,then layer rules, then volume or global rules. Within each category, asdescribed with reference to FIG. 8, user customizations are of higherpriority than default rules, other than safety or minimum functionalitydefaults.

FIG. 10K shows an alternative display approach to that of FIG. 10E-10J.The bottom portion of the display 1002 is similar to that of FIG. 10I,with the volume fill graph section VFG-B display element as a topographyrepresentation of approximately 150 layers, the same as or similar tothe volume fill graphs of FIGS. 10E-10H. As shown by the position of thethumb TH1, the currently displayed layer is layer 38 within rule sectionRS9, within which layers 4-44 and 107-147 include approximately 25%fiber fill as shown by the volume fill graph section VFG4, VFG5. A 3Drendering of the accumulated layers of the part is shown instead of a 2Dlayer plan view. Optionally, the 3D rendering is more transparent withrespect to fill material, walls; and comparatively less transparent forfiber material; optionally with additional luminance for highlightedsections of fiber material. As shown, section RS9 is selected viapointer PO1, and a fiber highlight FHL corresponding to the fiber tracksof rule section RS9 is arranged and/or highlighted within the 3Drendering of the part.

Accordingly, a machine implemented method for displaying 3D printablemodel shells on a display 1002 may include displaying a multidimensionalshell of a sliced model (such as the 2D additive manufacturing layerrepresentations of FIGS. 10E through 10J, or the 3D rendered additivemanufacturing model, mesh, or accumulation of layers representation ofFIG. 10K) on the display. An orthogonal bar OB1.1, OB1.2 is displayedtogether with the displayed shell(s) parallel to an edge of the display.A first proportional grouping bar RS1˜RS9 is displayed relative to afirst range, similarly/respectively RS1˜RS9 of the orthogonal bar OB1.1,OB1.2, the first proportional grouping bar RS1˜RS9 representative of afirst toolpath rule (e.g., no fiber, concentric, isotropic) common to afirst range of shells at index positions within the range. A movement ofa pointer PO1 in a direction relative to the display and/or an actuationof the pointer is detected (e.g., a mouse click; a touchscreen tap; abutton press associated with pointer). In response to detecting themovement and/or the actuation of the pointer PO1, one or both of thetoolpath rule or the range is changed. For example, in response, theprinter or its slicer processing may be configured to change the firsttoolpath rule common to the first range of shells to a different, secondtoolpath rule common to the first range of shells. In the alternative orin addition, the printer or its slicer processing may be configured tochange the first range of shells to a different, second range of shellshaving the first toolpath rule common thereto. Subsequently orsimultaneously, the printer or its slicer processing may be configuredto change the displayed multidimensional shell of the sliced model sothat the change of the toolpath rule and/or the change of the range ofshells is one of highlighted or displayed.

FIG. 11A-11D show an exemplary display on the view panel 1002, and eachis generated by rendering to each display 2D definitions (optionallypresented in 3D) of contours, subcontours, and toolpaths, with optionalprocessing for occlusion and showing and hiding particular featuretypes. In FIGS. 11A-11D and in like representations described in thisspecification, regions/subcontours may be shown with dotted lines; fibertoolpaths with grayscale, wider lines; and matrix or resin filltoolpaths with solid lines (excepting short, dark segments extendingbetween fiber toolpaths, which represent crossovers in S, L, or Ushape). In some a toolpath may represent either resin/material fill orfiber (e.g., for honeycomb, triangular, or other volumetric sparsefill).

FIGS. 11A-11D also corresponds to the toolpaths generated by theoperation of FIG. 10A-10I (display), FIGS. 8 through 9A-9D (processcontrol), FIGS. 5A, 5B (rule sets and data structures). As defined bycontours, subcontours, and toolpaths, the exemplary part as initiallyconfigured to be printed represents a layer definition of slicing to thepath generator, a display on the view panel; a definition of contours,subcontours/regions; and a definition of a subset of toolpaths. In FIG.11A and similar figures, a notation with “X” indicates a layer isrepeated, e.g., a number of times, (possibly through a cycle ofcomplementary layer patterns) that number of times, e.g., “90×” means 90adjacent layers forming a set.

Fiber reinforcement strategies, which may in some cases be used incombination and which may have sub-strategies, include ConcentricInward, Boustrophedon (ox rows, also known as raster, or as isotropic,or quasi isotropic when the direction of rows is rotated or alternatedin adjacent layers), Concentric Outward, or Sandwich Panel.

Concentric fill is performed within a layer by first obtaining 80-105%(preferably 85-99%) fiber-width offsets from an outer perimeter of aregion of the layer. That is, the offsets form concentric paths that are80-105% (preferably 85-99%) of the fiber-width as laid. One advantageousglobally set region is the non-wall region adjacent a shell or wallthickness region (e.g., 1-3 bonded ranks thick). Fiber is deposited bycontrolling the deposition head to stroke the center of the concentricfiber fill offsets. When the offset has been looped, an S-shaped,L-shaped or U-shaped crossover or bend lays fiber into the neighboringoffset. Concentric fill is suitable for bending and tension loads inparticular, and is efficient (fewer turns) as well as inherently strong(no fiber separation permits more force to be transmitted anddistributed along the fiber length). As a global setting, concentricfiber fill may be set to be adjacent a floor and or a roof, and/or at aset number of layers from the top and/or bottom of the part. In thealternative, spiral or concentric fill may have no particularorientation, as its direction depends on the perimeter of the part.Optionally, the concentric fill algorithm may be used for otherstrategies (e.g., for surrounding holes or hole splines forreinforcement). As noted, other settings can be used in combination to,e.g., migrate the crossover or bend between layers, locate crossovers ina particular place, or repeat or vary concentric fill patterns.

Ox-row fill or Raster fill is performed in back and forth rows. U.S.Pat. No. 6,934,600, herein incorporated by reference in its entirety,discloses various implementations of raster fill for nanotubeimpregnated three dimensional printing. Ox-row fill is performed byspecifying an orientation of rows (e.g., lengthwise, widthwise, or at aspecified angle) and a region. One advantageous globally set region isagain a non-wall region adjacent a shell or wall thickness region.Parallel straight rows, offset by 80-105% (preferably 85-99%) of thefiber width as laid, are calculated side by side traversing the region.If a cutter is available sufficiently close to the tip of the depositionhead, the fibers may be cut at each turn, alternating turns, every 3turns, according to a desired fiber length, and so on. However, aboustrophedon path is optional. Boustrophedon paths can be connected atend rows by 180 degree curved fiber paths of the same diameter as theoffset, and/or by folded paths of two right angles (these mayalternate). Fiber is again deposited by controlling the deposition headto stroke the center of the concentric fiber fill offsets. When theoffset has been looped, an S-shaped crossover lays fiber into theneighboring offset. As a global setting, ox-row fiber fill may be set tobe adjacent a floor and or a roof, and/or at a set number of layers fromthe top and/or bottom of the part. Ox-row fill may be set tosubstantially repeat a direction of fill (for increased cumulativestrength in that direction, or to provide arbitrary or predeterminedpatterns of two, three, four or more varying directions to increasemulti-directional strength (e.g., 90-90 would represent two adjacent 90degree perpendicular layers; 60-60-60 three adjacent layers each rotated60 degrees, 45-45-45-45 or 90-45-90-45 four layers following a repeatingpattern of reinforcing crisscrossing layers).

In this regard, successive layers of composite may, like traditionallay-up, be laid down at 0°, 45°, 90°, and other desired angles toprovide part strength in multiple directions and to increase thestrength-to-weight ratio. The controller 20 may be controlled to depositthe reinforcing fibers with an axial alignment in one or more particulardirections and locations. The axial alignment of the reinforcing fibersmay be selected for one or more individual sections within a layer, andmay also be selected for individual layers. For example, as depicted inFIG. 11H a first layer 1200 may have a first reinforcing fiberorientation and a second layer 1202 may have a second reinforcing fiberorientation. Additionally, a first section 1204 within the first layer1200, or any other desired layer, may have a fiber orientation that isdifferent than a second section 1206, or any number of other sections,within the same layer.

Concentric fiber outward fill is distinct in from concentric fill inthat (i) the fiber loops are offset from an inner perimeter formed by anenvelope about features or parts to be spanned, rather than outside in.Otherwise, the description with respect to concentric fill applies aswould be understood by one of ordinary skill in the art. Fill isperformed within a layer by first determining an interior region to besurrounded, e.g., first obtaining an envelope about two features to becircled. Offsets are generated at 80-105% (preferably 85-99%)fiber-width from an outer perimeter of the envelope. Fiber is depositedby controlling the deposition head to stroke the center of theconcentric fiber fill offsets. Any S-shaped, L-shaped or U-shapedcrossovers may be concentrated on the lengthwise ends, i.e., the curves.of the loops. Alternatively, as with concentric, a “spiral” offset oflinearly increasing offset distance may be used to avoid crossovers, buta spiral offset typically does not fully wrap features such as holes.Optionally, the envelope generation and inner perimeter start may beused for other strategies. Through-hole fill, as an example, may treateach hole as an envelope, and extend the fill from top to bottom of thepart, lining a hole along greater than 80 percent of its top-to-bottomlength. As noted, other settings can be used in combination to, e.g.,migrate the crossover between layers, locate crossovers in a particularplace, or repeat or vary concentric fill patterns.

As an example, the embodiment of a part rendered and processed as shownin FIGS. 11A-11D include, but are not limited to, the operation of thefollowing rules:

(i) concentric fiber fill in the region R08 between the outermost wallregion R06 and the neighboring region R10;

(ii) pure polymer, fill material, or fiber triangular infill in theregion R10, which may be a remainder region (set after the other regionsare defined) extending between the limits of the fiber fill region R08and the negative contour W02, W04 outlining wall regions R02, R04.

(iii) a sandwich panel, outer shell, inner shell, outer/inner shell, orcellular rule as discussed below; and

(iv) a rule to outline or reinforce holes as discussed below, amongother rules.

It should be noted that although similar regions in FIGS. 11A-11D andfigures of similar appearance are similarly labeled for the purpose ofdiscussion, a region is in most cases recorded a per-layer entity, andmay be encoded as associated with other regions, as part of a set, orotherwise.

As defined in a data structure and rendered in FIGS. 11A-11D, beginningat the first printing surface (shown at the bottom in FIG. 11A, butwhich may be at the top for printing techniques which build down), alayer set L02 includes multiple slices (e.g., 5× slices at 0.1 mm for a0.5 mm height) through the torque transmitting feature F02 and slip fitfeature F04 shown in FIG. 10A. Each layer of set L02 is shown with fourregions: three wall regions R02, R04, R06 at each of outer positivecontour W06 and two inner negative contours W02, W04, as well as a denseor solid fill region. Layer set L02 includes successive layers of“floor” following the number of floors set as a parameter, and may be“solid” filled (e.g., having a toolpath for unreinforced material orplastic that fills in the entire layer, either by tight raster/ox rowfills or offsets).

Layer set L04.1 is generated by various rules, and includes, but is notlimited to, six regions in each layer: the three wall regions R02, R04,R06 of lower layer set L02 reproduced and/or extended, a sparse fillregion of triangular cells R10, and a fiber concentric fill region R08.The concentric fill region R08 as a “fiber fill” would be generatedafter the walls R02, R04, and R06, but before the sparse fill region R10(e.g., per steps S8562-S560 of FIG. 9A). As shown in FIGS. 11A-11D, theconcentric fill rule observes the precedence of the wall or shell rule(e.g., contour walls are 3 shells thick, as set and recorded by defaultor by parameter entry similar to FIG. 10A), and generates threesuccessive offsets (per, e.g., parameter P06 of FIG. 10A). As discussedherein, a “rule” may take the form of a subroutine, class, object,script, state machine, or other executable code; and/or of a set ofsequential primitive operations. Crossover toolpaths TP06 are shown inan exemplary default position. Three fiber layers are set as parameterP06 in FIG. 10A (from an exemplary available 1-10, but fiber layers maybe set up to and including the entire set of layers).

Layer set L04.2 is similar to layer set L04.1 (may be identical, or maybe complementary). The operation of a sandwich panel rule as set byparameter P12 in FIG. 10A creates two layers sets L04.1 and L04.2separated by a sparse infill layer set L06. A sandwich panel rule orfill may be considered a special case or combination of other fills,under operation of a combination rule. In the case of sandwich panelfill, two sets of multi-layer fiber fills (such as concentric, ox-row orox-row in four 45-45-45-45 angled layers) are separated in the directionof printing. Between these two sets, a cell-based infill provides a webconnecting the strong layers. Different processes may be used to arrangethe sandwich panel. In one embodiment, a rectangular prism nucleus isexpanded to fill the interior space available (e.g., until abuttingexterior shells/walls, floors, and or/roofs), and at least one top andbottom layers of the prism are fiber filled with the selected fiberpattern (e.g., concentric, ox-row or 4 layers of ox-row at 45-45-45-45angles), with the intervening layers being filled with a cellular infill(optionally with fiber cellular infill, as discussed herein). In anotherembodiment, a start layer having a substantial interior region is filledwith fiber (e.g., a layer adjacent a floor or roof occupying more than50% of the layer area, or a layer having the greatest area), and if thesubstantial interior region is repeated in parallel for a certain numberof layers (e.g., 100 layers), then the sparse polymer infill is againfilled.

The sandwich panel rule set by parameter P12 is shown in combination inFIG. 11A, optionally in FIGS. 19D-19E with the concentric fill or aquasi-isotropic fill rule, and operation of other rules arecomplementary. In some cases, the additional rule will act as aparameter of the sandwich panel rule and change the operation of thatrule. For example, if parameter P11 is set to ox-row fill, the fill inlayers L04.1 and L04.2 may be carried out in a tight “raster” pattern asdiscussed in U.S. Pat. No. 6,934,600, or collectively rotating anglequasi-isotropic pattern, but would remain several layers with fiber fillL04.2 separated by many more sparse infill layers L06 from another setof complementary layers L04.1 to complete a part particularly strong inbending because of the increase effective moment of inertia of thesandwich panel form. In other cases, the additional rule would operateseparately in a predetermined priority or order of operation. Forexample, when the “reinforce through holes” rule of parameter P14 isset, either or both of the holes through torque transmitting feature F02and slip fit feature F04 would be surrounded and reinforced bygenerating offsets about higher priority protected regions, extendingfrom top to bottom (L02 . . . L10), as modified by other parameters.FIG. 11E shows a reinforced through hole of this type, although in thecase of FIG. 11E the hole is reinforced by a region extrusion operationrather than a global rule.

In addition, the sandwich panel rule or fill may incorporate shells inthe manner shown and describe with respect to FIGS. 19D-19J, in part orin whole, and embedded within a part or extending to the outer shell.The structure of FIG. 19E may be created with the operation of asandwich panel rule in which, similar to layers L04.1, L04.2, and L05,concentric fill creates offsets from the outermost protected region (inthe case of FIG. 19E, without an outermost protected unreinforced resinwall). The structure of FIGS. 19F and 19G may be created with theoperation of a sandwich panel rule in the case of FIG. 19F in which theconcentric fill is set to a higher number of fiber shells toward theperimeter of the (e.g., twice as many as outer layers on the centroidside, which could be carried out herein at least as a global rule, aregion edit, a layer edit, or a dropped library object), or in the caseof FIG. 19G in which a higher number of fiber layers is set. Similarly,the structures of FIGS. 19H-19J may be created with the operation of aquasi-isotropic set sandwich panel rule for pattern 1352-QI, an outerconcentric rule for pattern 1352-O.CON, an inner concentric rule forpattern 1352-I.CON and/or 1350-IF. A wafering rule may create thesuccession of separated quasi-isotropic sets 1352-QI as in FIG. 19J, anda cellular fiber infill rule may create the cellular fiber infill walls1352-CLW and/or 99Z as shown in FIG. 19J.

Continuing with FIGS. 11A-11C, layer set L06 is generated by a roofparameter variation which specifies that additional walls L06B must besurround the inner and outermost walls of outer and inner contour wallsregions L06A, in order to provide anchor points for the solid or densefill in the lowermost roof region (in this case, the initially formedanchor walls may be overrun by the toolpath of the sparse fill toprovide the anchor). Layer set L06 is generated by a roof rule similarto the floor rule of layer set L02, and layer set L10 completes thetorque transmitting feature F02 and slip fit feature F04 with dense fill(e.g., 90 layers at 0.1 mm, for 0.9 cm height).

Any exception fill (e.g., per step S8568 of FIG. 9A) may be of secondlowest priority and conducted before the remainder sparse infill,optionally with special control parameters. For example, should anyinterstitial distance between bonded ranks formed between borders ofregions R02, R04 and the fiber fill region R08 be smaller than the widthof the nominal width of fiber printing, a slower extrusion, highertemperature, slower feed speed, slower curing speed, or the like of pureresin fill may be tuned to inject or deposit fill into the interstitialarea before the remainder pattern fill is used to sparsely reinforce theinterior. An exemplary interstitial, exception fill is shown as region12 of FIG. 10D. In this situation, changes made to fiber pathing via thetools of FIG. 10C may create an interstitial area between a fiber regionand negative contour wall region, which is optionally treated as anexception to the sparse infill region R10A.

Accordingly, the operation of the global rule set, in the form ofexecutable code or parameters controlling parameterized executable code,permits automated path generation, and global customizations. As noted,although the global rule set is in one embodiment of lesser prioritythan path, region, or layer customizations, it may be the firstsequential rule set that conducts toolpath generation.

In one embodiment, the per-layer operation rule set and order ofoperations includes a subset or superset of the global operations shownin FIG. 9A, but is essentially similar. The user (or an automatedoverriding function) may change many of the global rules on a layer bylayer basis. Layers are, or are optionally, each processed in the ordershown in FIG. 9A.

FIG. 11E shows a second exemplary region select and extrude operationper FIGS. 9C and 10D. As defined in a data structure and rendered inFIG. 11E, beginning at the first printing surface, a layer set L40 of“floor” layer includes one representative slice (although more floorswould be used in practice, this layer is not used in the example). Byprior operation—for example a layer rule and/or, a toolpath rule and/oredit, or a prior region rule and/or edit, layer set L42 includes threeregions R20, R22, R24 having concentric hole reinforcement, extendingthrough three layers.

Using the tools of FIG. 10D and the operations of the processes of FIG.9C, the user sets the current layer to the top layer of layer set L42,and selects the region R24 with the region selection tool. The region isextruded, using the region extrusion operator, up five layers, throughlayer sets L44 (roof layers of similar contour) and L46 (circular mountsof much smaller contour). Should the region R24 not extrude well intothe smaller contour, it can be shaped using the tools and operators. Forthe present example, the region R24 replicates unchanged in form as anextrusion, now regions R26-34. The user receives a warning that a globalrule is in conflict (i.e., a global rule requirement of a roof in thetopmost layer of the part, of layer set L46), and declines to overrulethe global rule. Having committed the extrusion, the user is promptedwith a choice of fills (e.g., selectable from (i) the same identicalfill as the parent region, (ii) a newly pathed fill of the same type asthe parent region, or (iii) a new fill of any compatible type). The userselects identical fill, which is propagated (contingent on anyoverriding global rules) to the penultimate layer of layer set L46.

Accordingly, the operation of the region level rule set, in the form ofexecutable code or parameters controlling parameterized executable code,permits automated region generation, and region customizations. Asnoted, although the region rule set is in one embodiment of lesserpriority than path, but greater priority than layer or globalcustomizations, this priority may be otherwise arranged.

The controller 20 of the printer 1000, may, as described herein, supplya multi-strand core reinforced filament 2 including a flowable matrixmaterial 4 a and a plurality of substantially continuous reinforcingstrands 6 a. The strands are preferably of a material having an ultimateor tensile strength of greater than 300 MPa (e.g., see Materials table).The substantially continuous reinforcing strands 6 a extend in adirection parallel to a length of the filament 2. The controller 20 ofthe printer 1000 controls the actuators and heaters to deposit a firstconsolidated composite swath 2 c of a height less than ½ the width ofthe filament 2 in a first reinforcement formation, e.g., 99A-99Z,including at least one straight path 991 and at least one curved path992. Curved paths include both (i) curves in which the corner radius isgreater than 2 times the composite swath 2 c width—as deposited—as wellas, or in the alternative (ii) sharp corners, as unfolded or foldedcorners, having a corner radius from 0 to twice the composite swath 2 cwidth. The controller 20 of the printer 1000 controls the actuators andheaters to flow the matrix material 4 a and applying an ironing forcethat spreads the reinforcing strands 6 a within the filament 2 a againsta deposition surface 16, 14, or 2 d (once spread, the material may beconsidered a bonded rank or consolidated swath 2 c).

The controller 20 of the printer 1000 controls the actuators and heatersto deposit a second consolidated composite swath 2 c, optionally also ofa height less than ½ the width of the filament, in a secondreinforcement formation 99A-99Z including at least one straight path 991and at least one curved path 992, by flowing the matrix material 4 a andapplying an ironing force to spread the reinforcing strands 6 a withinthe filament 2 and/or second consolidated swath 2 c-2 against the firstconsolidated composite swath 2 c.

Yet further alternative or additionally, the controller 20 of theprinter 1000 controls the actuators and heaters such that the firstconsolidated composite swath 2 c and second consolidated composite swath2 c are deposited in a location adjacent to and reinforcing a negativesubcontour. In this case, “reinforcing” means following or tracing alonga perimeter, wall, load line, stress concentration, or a trajectorydrawn between the same. “Adjacent” means immediately adjacent, and alsoseparated by a small number (e.g., 1-5) of coating, smoothing orcompliant neat material 18 a walls, floors, or ceilings. A negativesubcontour may be a hole, or an embedded material or object or set-asidefor same, or a second object with surfaces intruding into the layer or aset-aside for the same, or an overmolding, or in some cases a touchingloop surrounding a hole, embedded object, or intruding object. In thistechnique, alternatively or additionally the first consolidatedcomposite swath 2 c and second consolidated composite swath 2 c may bedeposited in respective (adjacent) first and second layers LA_(n),LA_(n+1) in locations adjacent to and reinforcing a negative subcontourextending through each of the respective first and second layers LA_(n),LA_(n+1).

In some embodiments, a core reinforced filament 1854 is used to form ahole directly in a part, see FIGS. 11F and 11G. More specifically, thecore reinforced filament 1854 comes up to the hole, runs around it, thenexits from the direction it came, though embodiments in which thefilament exits in another direction are also contemplated (e.g., FIGS.13A-13C). A benefit associated with this formation method is that thehole is reinforced in the hoop direction by the core in the corereinforced filament. As illustrated in FIG. 11F, the core reinforcedfilament 1854 enters the circular pattern tangentially. Enteringtangentially is good for screws that will be torqued in. In anotherversion illustrated in FIG. 11G, the core reinforced filament 1854 enterthe circular pattern at the center of the circle. Of course, it shouldbe understood that other points of entering the pattern are alsopossible. In one embodiment, the entrance angle may be staggered in eachsuccessive layer. For example, if there are two layers, the enteringangle of the first layer may be at 0 degrees while the entering anglefor the second layer may be at 180 degrees. This prevents the buildup ofa seam in the part. If there are 10 layers, the entering angle may beevery 36 degrees (e.g., staggering the entering angle by 360 degrees/10layers) or any other desired pattern or arrangement.

Still further alternative or additionally, with reference to FIG. 20,the controller 20 of the printer 1000 may control the actuators andheaters such that depositing the first consolidated composite swath 2 cand the second consolidated composite swath 2 c as a continuouscomposite swath 2 c spanning (e.g., via inter-layer continuous traverseSP30-A, SP30-B) two shells LA_(n), LA_(n+1) of an additive manufacturingprocess.

Still further alternative or additionally, the controller 20 of theprinter 1000 may control the actuators and heaters such that the firstconsolidated composite swath 2 c is deposited in a first reinforcementformation 99A-99Z that has a higher strength in tension between a firstnegative contour (or hole H_(a)) and a second negative contour (or holeH_(b)) than the second reinforcement formation 99A-99Z.

The secondary print head 18 prints fill material to form walls, infill,protective coatings, and/or support material on each layer, and asdescribed herein, to smooth over protrusions into neighboring layers.

Consolidation, Compression and/or Flattening of Composite Swaths

A preferred technique for depositing a core-reinforced filament tobecome a fused composite swath includes compressing a core reinforcedfilament exiting a conduit nozzle to form a flattened shape (asdiscussed in the CFF patent applications).

The flattened shape is of variable height-to-width proportion, e.g., incross-section from 1:2 through about 1:12 proportion. Preferably, theheight of a compressed composite swath 2 c substantially corresponds tothe fill material layer height in the same layer LA₁, so thatneighboring composite swaths 2 c in the vertical direction can betightly packed, yet be built up as part of the same or adjacent layersas the surrounding, complementary and/or interstitial fill material 18a.

Inter-layer interaction among composite swaths 2 c and fill material 18a may be more involved than interlayer interaction among layers of fillmaterial 18 a. In most cases, an optional requirement for adjacentlayers of fill material 18 a is that they are satisfactorily fused inthe vertical direction to avoid delamination, and in many cases the fillmaterial 18 a is fused (melted, or cured) under ambient or roompressure.

A core-reinforced multi-strand composite filament 2 may be supplied, forexample, as a circular to oval cross section, and/or of approximately ⅓mm in diameter and/or “13 thou” diameter.

As shown in Table 1 below, a circular cross-section filament 2compressed during deposition becomes a progressively wider compositeswath 2 c. The table uses an example dimensionless diameter of 3 unitsfor “round numbers”.

As shown in the table, for any size of substantially circular crosssection core reinforced filament 2, flattening to about ⅓ of itsdiameter becomes about 2.2-2.5 times as wide as its original diameter,and if flattened to about ½ its diameter becomes about 1.4-1.7 times itsoriginal diameter.

TABLE 1 Example Diameter (Circle): 3 units Rectangle Compression H W ⅔ Dheight ~2 ~3½ ½ D height ~1½ ~4½ ⅓ D height ~1 ~7 ¼ D height ~¾ ~9½

For example, to complement an additive manufacturing layer height of 0.1mm, a ⅓ mm diameter core reinforced filament 2 may be flattened to acomposite swath 2 c of roughly rectangular shape of proportion 1:6through 1:12 (herein “highly compressed”), e.g., about 0.7-1.1 mm wideby about 0.07-0.12 mm high. One preferred ratio is roughly 1:9. Evenhigher compression may be possible, e.g., 1:12 to 1:20, but may demandsignificant system stiffness in the printer 100.

In contrast, to complement an additive manufacturing layer height of 0.2mm, a ⅓ mm diameter core reinforced filament 2 may be flattened to acomposite swath 2 c of roughly rectangular shape of proportion 1:1.5 to1:4 (herein “lightly compressed”), e.g., about a roughly rectangularshape of about 0.4-0.6 mm wide by about 0.2 mm high.

However, a fiber-embedded rectangular cross section of 1:1.5 to 1:3 isnot as compressed or consolidated as one of 1:6 to 1.12 proportion, andin many cases, an relatively higher amount of consolidation ispreferable to reduce voids and improve mingling of fibers in adjacentranks 2 c-2 c or 2 c-2 d.

It should be noted that a supplied fiber reinforced filament 2 may havea constant cross-sectional area as supplied and as deposited (unlesscoextruded or supplemented); while a supplied FFF filament 18 a has botha very different cross-sectional area as supplied and as deposited(having a much larger diameter as supplied), as well as variablecross-sectional area as deposited (having a bead size depending onextrusion rate). Given that a highly compressed composite swath ispreferable to a lightly compressed one, combining a larger FFF extrusionrate layer height (e.g., 0.3 mm) with a highly compressed compositeswath (e.g., 1:9 ratio) may be challenging. Accordingly, when a fillmaterial height is such that the amount of compression is unacceptablyreduced, more than one layer of fiber may be arranged per layer of fillmaterial (e.g., 2 or 3 1:9 sublayers of 0.1 mm composite swath 2 c perone respective 0.2 or 0.3 mm layer of fill material 118 a). In thiscase, most or all fill material 18 a is deposited after the compositeswaths 2 c; although in an alternative mode self-collision detection maybe used to avoid contacting the nozzles to the part and the order ofdeposition thereby varied. In addition, in a modification of thisprocess, the fill material height and compression amount may be selectedto match stacks of 1:6-1:12 “highly compressed” composite swaths 2 c(e.g., for a fiber of ⅓ mm diameter, the matching fill material 18 alayer height capped at approximately 0.24 mm, because the highestacceptable “highly compressed” stack of two fibers is 1:6 ratio×2, or0.12 mm×2).

It should be noted that the cross-sectional representation ofreinforcing strands 4 a within filament 2 a and deposited swaths 2 c areschematic only. In most cases, the reinforcing strands are in thehundreds to thousands of parallel strands within the filament 2 a orswaths 2 c.

Linkage Arm: Layer Toolpaths

FIGS. 12A-12J show composite swaths and/or path planning for layers oflinkage arms or base plates. Herein, “linkage arm” or “base plate”includes e.g., any member having at least two holes H1, H2; H3, H4; H5,H6 which may link two additional members or support the connecting plateat two locations to a supporting member, inclusive of linkages,brackets, and the like. The linkage arms or connecting plates showninclude hexagonal holes H1, H2, square holes H3, and round holes H4, H5therethrough, and different combinations of these. In each case, a topdown view presents a single layer view of an additive manufactured or 3Dprinted part, and in each case a few (three or four) cycles ofoutlining, following, or tracing approach for the composite swaths 2 cand/or toolpaths, while in many cases the pattern of spiraling,offsetting, rastering, or sparse fill honeycomb may be continued to thelimits of a cross-section, contour, or a neighboring section ofspiraling, offsetting, rastering, or sparse fill honeycomb. As discussedherein, a typical vertical pitch or layer height for a 3D printed partis 0.1-0.3 mm (although coarser and finer layer heights may be used, aswell as different layer heights within the same part). Accordingly, fora 0.1 mm layer height, a 1 cm high part would have 100 layers, and a 30cm high part would have 3000 layers. In each case, two holes H1-H5 areshown although the same principles extend to multiple holes, negative,embedded or overmolded contours.

FIG. 12A shows a single layer of a connecting plate having two hexagonalholes H_(a), H_(b) (here labeled H1, H2). In several figures, includingFIG. 12A, as shown, contours or region followed by the strategy arecoincident with the hole wall. Alternatively, the contour or regionfollowed may be offset from the hole wall (e.g., representing wallthicknesses of fill material 18 a). In FIG. 12A, a reinforcementformation 99A having a spiral tracing strategy is used to follow the twointernal contours of the hexagonal holes H1, joined by a shortestpossible line (linking H1 and H2). As shown in FIG. 12A, the spiraltracing strategy begins B1 the toolpath on a side of a hexagonal holeopposite to the swaths extending between the two holes H1, H2, and is“anchored” on that side (i) against the hole wall (ii) by the angledcurve about the hole wall and/or (iii) by surrounding composite swathsin the second and subsequent cycles/loops. The swaths 2 c extendingbetween the two holes H1, H2 may be expected to carry load in a tensionmode, and the swaths 2 c closely surrounding the holes H1, H2 may beexpected to reinforce the walls of the holes H1, H2, in a combinedtension-compression mode. The spiral toolpath ends E1 on the same sideas it began in a proximate position, on a side of a hole H1 opposite thetension-bearing swaths, but may optionally be further “wound” about thehole H1 to improve “anchoring” (e.g., increase that length of fiberfused in matrix material and fill material that directly bears tensionloads at the interfaces between fiber surface, matrix material, and fillmaterial). While this strategy is of a toolpath spiraling outward frominternal contours H1, H2, a very similar toolpath can be built in aninward direction (i) in the case where the outer contour of the part 14,LA₁ is shaped similarly to an offset of the holes H1, H2 and joiningline or (ii) where a region bounding toolpath generation is set as ashape similar to an offset of the holes H1, H2 and joining, shortestdistance line. For example, a composite swath 2 c reinforcementformation 99S or toolpath may be generated by defining an internalregion of the part 14, LA₁ as an origin for offset tracing starting froman outer contour and offsetting inwards.

FIG. 12B shows a toolpath, composite swath, or reinforcement formation99B similar to FIG. 12A, a single layer LA₁ of a connecting plate havingtwo hexagonal holes, H1, H2 with a spiral tracing strategy is used tofollow the two internal contours of the hexagonal holes H1, H2. In thiscase, in order to shift the stress concentration and Y-shape at whichpaths meet to a different location in at least one orthogonal directionand/or along the perimeter of a hole H1, the shortest line from whichspiral tracing is offset or spiraled is shifted up along a hole boundaryto a position displaced from the former stress concentration location inat least two orthogonal directions (e.g., in the X and Y directions asshown, and also in the Z direction as the displaced stress concentrationis in a the next layer). FIG. 12H shows four superpositions, i.e.,layers of this pattern, mirrored vertically and horizontally, todistribute the stress concentrations variously among the four layers. Asdiscussed, the pattern or reinforcement formation of FIG. 12A may becombined with that of FIG. 12B for further combinations. It should benoted that for illustration purposes, each of the hexagonal, circular,and square holes represented throughout are generally of similardiameter or width, and the patterns can be variously combined asdisclosed herein when not inconsistent with a hole shape or width (andwith adjustment that would be readily understood by those of skill inthe art). As an example, the patterns of FIGS. 12C and 12D are shownwith both circular and hexagonal internal regions or contours at thehole locations (hexagonal holes and circular outline regions), and thesepatterns are suitable for surrounding and reinforcing hexagonal andcircular holes.

FIG. 12C shows a looped toolpath with minimum corners and gentle turns,formed with a spiral building outward from an envelope about circleregions R6, R8 surrounding respective hexagonal holes H1, H2 (optionallycircular holes), a minimum composite swath length path that surroundsboth holes H1, H2. This reinforcement formation is suitable for (i)tension loads between the two holes because of the several well-anchoredand continuous loops. This reinforcement formation 99C is also suitablefor (ii) transmitting torque about the holes, as rather than followingthe hexagonal hole walls, the circular regions circumscribing thehexagonal holes are reinforced with composite swaths along the directionof hoop stress encircling the holes. However, this toolpath/compositeswath/reinforcement formation 99C as deposited does not particularlyreinforce the straight walls of a hexagonal hole, and could therefore beused in combination with, e.g., a toolpath of FIG. 12A or 12B, or as inFIG. 12F or 12G in order to reinforce such walls.

FIG. 12D shows a toolpath, fiber or composite swath pattern, orreinforcement formation 99D which reinforces in a loop about each of twohexagonal holes H1, H2 (or circular holes or regions R6, R8). FIG. 12D,which generally does not place a majority of composite swaths in atension arrangement between the two holes H1, H2, may be more suitablefor repeating throughout the entire height of a part, or together withan interior sandwich panel honeycomb portion of a part 14, in order toprovide each hole H1, H2 with a solid tube of fiber reinforcement fromtop to bottom, to provide compression resistance vs. tightening of boltsor the like through the holes H1, H2. FIG. 12D also demonstrates thatoffset toolpath generation (left, e.g., see offset crossovers at OF1)and spiraling toolpath generation (right, e.g., see spiral start andfinish at SP1) can be used in the same part, layer, or even toolpath,and FIG. 12I, which repeats the reinforcement formation 99D in differingorientations throughout several layers, shows that the stressconcentrations/gaps in different kinds of toolpathstrategy/reinforcement formation and different locations can be varied.Varying can be accomplished, for example, by mirroring horizontally andvertically, and again, optionally by varying, regularly or randomly, thelocation of pattern crossovers, overlaps, starts, finishes, and/or gapsand about the periphery of the surrounded hole, feature, internalcontour, embedded contour, negative contour, or overmold contour).

FIG. 12E shows a variation of FIG. 12F in which the toolpath, compositeswath pattern, or reinforcement formation 99E is of offset approach,with crossovers OF02 at the opposite side of the part from the spiralstart and end of the spiral strategy toolpath of FIG. 12F. FIG. 12Fshows a toolpath, composite swath strategy or reinforcement formation99F similar to FIG. 12C, as a spiral strategy, excepting that FIG. 12Fshows a paired square hole H2 and circular hole H5 (e.g., for a torquearm application, alternatively replacing the square hole H3 with acircular fitted hole corresponding to region/contour R9) FIG. 12J showsthe superposition of these toolpaths or composite swath depositions orreinforcement formations 99E, 99F of FIGS. 12E and 12F over two layers,placing the stress concentrations and/or gaps of the offsets and/orspiral start and end in positions displaced from one another in at leasttwo orthogonal directions (here, substantially the X direction as wellas the Z direction between layers). The controller 20 of the printer 100causes the actuators and the heaters to turn the first fused compositeswath 2 c-1 according to the first reinforcement formation 99A-99Ztoward a different direction at a first location, e.g., OF2. In printingthe second reinforcement formation 99A-99Z, the printer 100 turns thesecond consolidated composite swath 2 c-2 according to the secondreinforcement formation toward a different direction at a secondlocation e.g., SP05 displaced from the first location OF2 in at leasttwo orthogonal directions (in this case, by example, in X and Zdirections).

FIG. 12G shows two concentrically located toolpaths or composite swathstrategies or reinforcement formations 99G, 99H surrounding the sameholes H_(a), H_(b) (here labeled H3, H5), in order to relativelydisplace or distribute gaps, seams and stress concentrations to limitpropagation of cracks or other modes of failure from nucleation at agap, seam, or stress concentration. In addition, the patterns 99 g, 99Hare biased to angle between the holes, so that it may be mirrored orvaried to provide a variety of different and complementary fiberorientations among layers, especially in a direction complementing theloading profile. For example, mirroring the patterns 99G, 99H amonglayers about the X axis will provide added tensile strength along the Xaxis, and should the layers containing such patterns be distributed toouter layers in the Z direction, provide added bending strength versusbending about the Y axis. The inner pattern or reinforcing formation 99His an offsetting pattern with offset crossovers OF03 located at thecorner or junction between the longer swath segments between holes andthe circular hole H5 (e.g., at the upper left hand side of the roundhole); and the outer pattern or reinforcement formation 99G is a spiralpattern with the start of the spiral OF03 abutting a corner or junctionformed in the previous pattern (e.g., at the lower right hand side ofthe pattern previously formed about the square hole H3).

Complementary Reinforcement Formations

Disclosed herein are complementary toolpaths, composite swath depositionstrategies, or reinforcement formations 99A-99Z—first, second, and otherformations—for both composite swaths 2 c and fill material 18 a withinlayers and in adjacent layers, was well as overlaps within a layer, suchas same-layer crossing turn overlaps and same-layer parallel overlaps.In addition, “smoothing over” and “attenuation” strategies within oradjacent reinforcement formations 99A-99Z avoid accumulation of, inparticular, fiber material overlap protrusions over several or manylayers. Such strategies can also be used to ameliorate accumulation oftolerance stack among many composite swath layers.

Using different formations may also permit horizontal repositioning ofstress concentrations, gaps, or seams arising from fiber routing in thehorizontal plane, as they may permit varying of positioning of startposition, end positions, runout accumulation or shortfall, and sharpturns in the composite swath 2 c. This is especially the case nearcontour boundaries, holes H_(a), H_(b), H_(c) etc. or negative contours,as well as channels and island contours, as localized reinforcement inmany cases means various sharp turns in the surrounding toolpath.Accordingly, a purpose of using different reinforcement formationswithin a layer and among layers is to distribute gaps, seams, and stressconcentrations to positions that are different from locations inadjacent or nearby layers, and/or in distributed positions among layers;as well as to permit different kinds of reinforcements for differentstresses to be distributed among layers.

For example, taking FIG. 12A as an example, the walls of hexagonal holes2A are to be reinforced by an inner-contour following spiral path ofreinforcement formation 99A. An inner-contour, outwardly spiralingtoolpath as part of reinforcement formation 99A may be synthesized toreinforce both holes H1, H2 and maintain continuity of long lengths ofcontinuous composite swath 2 c as much as possible, and/or providelengthwise reinforcement in entire part 14. A minimum area, minimumdistance connection (i.e., a zero thickness line “hole” negative contourR4) is synthesized between them. A spiral path—i.e., a path thatgradually changes offset distance from the contour being outlined ortraced, so as to continue in a spiraling fashion—is selected to form thereinforcing toolpath of reinforcement formation 99A. The spiral is begunat a position prioritizing the strength along the center of the partLA₁, 14 (e.g., at a position to the left side of the left hole H1, asshown). As shown in FIG. 12A, the walls of the left hexagonal hole H1are traced, then a path is taken directly paralleling the zero-thicknesscontour R4 to the right hexagonal hole H2, which is followed. Thetoolpath returns along the line of the zero-thickness contour R4 (on theopposite side, not overlapping in this case), and spirals about the lefthexagonal hole H1 and the previously placed toolpath, and so on, forapproximately three “laps” of the “track”.

As shown in FIG. 12A, while the walls of the hexagonal hole H1 arereinforced, various gaps, seams, and stress concentrations may becreated in the composite swath direction changes and corners. Inparticular, the entrance/exit zone includes a corner SC01 that is notreinforced by fiber, and which includes various stress concentration atthe Y-shaped junction of the two track sections at the corner. If thispattern 99A is repeated for many layers of an additive manufacturingpart, the “seam” of stress concentration SC01 and lack of direct cornerreinforcement may be continued along this corner (that of thegap/seam/stress concentration SC 01) in the vertical direction (e.g.,extending for tens or even hundreds of layers). This may, for example,be addressed by maintaining a similar reinforcement formation 99B as inFIG. 12B, but moving or changing the junctions or turning locations ofthe “laps” among layers. For example (without overlapping within alayer), the location of a different but similar stress concentration andY-junction SC02 may be moved along the side of the hexagonal hole H1, asshown in FIG. 12B. This stress concentration location may be “moved”from SC01 to substantially to anywhere along the inner two sides of thehexagonal hole on either side, and may be thereafter throughout thelayers arranged in an organized, repeated, or randomized fashion. Forexample, FIG. 12H shows a repeating pattern over 4 layers in which thearrangement of FIG. 12B is mirrored horizontally, then vertically,providing 4 changed seam locations SC01, SC02, SC03, SC04 on fourdifferent layers. Similarly, the location of the spiral origin SP02 ismoved to 2 changed locations. Non-symmetric arrangements may besimilarly varied (by varying the entry/exit location along a particularpath, contour, or guide) regularly or randomly.

Different contour following strategies or reinforcement formationswithout internal overlaps or composite swath crossings within a layermay be layered among different layers. For example, the followingstrategy or reinforcement formation 99C of FIG. 12C is a (i) spiralfollowing of (ii) an inner contour, taking a (iii) shortest possiblepath (iv) including the two hexagonal holes. H1, H2 while (iii) makingno sharp corners (a “sharp corner” is an unfolded or folded cornerhaving a corner radius from 0 to twice the composite swath 2 c width).The strategy of FIG. 12C transmits hoop stress and longitudinal tensionstress with a smaller stress concentration than other strategies, andmay be combined with FIGS. 12A, 12B (primarily strategies forstrengthening walls of the holes together with resisting tension).

FIG. 12D is an exemplary strategy that could be mirrored in twodirections. The strategy of FIG. 12D uses (i) spiral following for oneside and (ii) offset following to the remaining side, both following thecontour of the hexagonal holes while (iii) making no corners, and onlyconnecting the two hole reinforcing zones by an single composite swathextending between. The connecting swath generally benefits if one of thefollowing patterns about the holes must spiral or connect to neighboringoffsets in an outward direction, and the following pattern on theconnected hole must spiral/offset inwards. The strategy of FIG. 12D usesreinforces in a hoop stress direction more than FIGS. 12A-12C, butleaves most tension reinforcement to other layers. Alternatively, FIG.12D, if repeated or repeated in a mirrored fashion from top to bottom ofa part, would reinforce the holes in compression vs. overtightening(e.g., as shown with circular holes in FIG. 12I).

As noted, individual reinforcement formation s 99A-99Z may be varied tovary distribution of isolated gaps, starting positions, end positions,and/or stress concentrations. Crossing points PR (i.e., crossingcomposite swaths within a same layer LA_(n)) may provide moreflexibility in the design of toolpaths of reinforcement formations99A-99Z, permitting more locations for seams to be distributed, as wellas additional forms should seams tend to stack among layers LA_(n),LA_(n+1), etc., or. Overlaps PR of composite swaths 2 c within a layerLA_(n) may create stress concentrations as relatively sharp turns in thecomposite swath 2 c upward and then downward are made, but withsufficient remelting, reduction in printing speed, feeding at a fasterrate than the printing speed to provide, or compression in overprinting,these path changes or turns may permit added horizontal repositioning ofstress concentrations arising from path planning in the horizontalplane, as well as avoiding turns in the composite swath leftward andrightward as the composite swath 2 c is permitted to continue in astraight path 991. This is especially the case at crossing turns PRabout holes and negative contours H_(a), H_(b), H_(c) etc., asreinforcement of a hole in most cases has an entrance and exit to thesurrounding toolpath of fiber/composite swath 2 c or reinforcementformation 99A-99Z, and the use of crossing turns can permit more freedomin locating that entrance/exit. Accordingly, a purpose of such crossingturns is to distribute gaps, starting and stopping positions, and stressconcentrations to positions that are different from locations inadjacent or nearby layers LA_(n−1), LA_(n+1), and/or in distributedpositions among layers LA₁ . . . LA_(m); as well as to permit differentreinforcements for different stresses to be distributed among layers.“Location” may mean in 2D or 3D location, along contours, or alongstress or load lines or fields.

In an alternative, for a second type of material, the controller 20 ofthe printer 1000 has uses one or more of higher than straight pathprinting speed, higher than straight path nozzle tip compression, and/orslower than printing speed filament feed rate.

Complementary Formations in 3D Core Reinforced Printing Vs. Laminates orFDM

Continuous carbon fiber composite laminates may be formed up in a“quasi-isotropic” (QI) four-ply or three-ply construction at 0, +/−45degrees, and 90 degrees. Anisotropically biased layups (e.g., 0, +/−30degrees, 90 degrees) are also used. The laminae are cut at the row ends.The reinforcement formations discussed herein for 3D printed compositeswaths 2 c may optionally be used in combination with QI construction.

FDM or FFF layers may be formed in orthogonal layers at +/−45 degrees ofalternating raster formation. Generally raster formation is preferred inorder to extrude hot, flowing plastic next to still-warm extrudate fromthe immediately previous row to improve bonding, with only minorconsideration for directional strength. The +/−45 degree rasterformation gives a multi-directional and satisfactory workable middlerange of tensile strength, +/−25% from the best and worst rasteringpatterns (e.g., 20 MPa UTS for ABS in 45-45 pattern, vs. about +5 MPafor longitudinal raster and about −5 MPa for transverse or diagonalraster). Note also that the better rastering patterns per loaddirection, which may place the direction of most of the extrudate roadsin the same direction as the load, may approach injection moldingstrength (e.g., about 95% of injection molding).

In 3D printing in a stranded-filament-to-ironed swath 2 c technique,both negative and positive contours may be reinforced beyond the matrixor fill material strength with continuous composite swaths looping aboutthe contour without severing the fiber. This in-plane looping isimpossible with composite layup, which cannot make turns within theplane without breaking the materials; and of different character andlimited effect with extrudate.

Different Modes of Reinforcement—Load Dependent

In the case of one, two, or more holes, negative contours, embeddedcontours, or overmolded contours in an actual part, in many casesdifferent kinds of reinforcement will be possible. For example:

(1) Reinforcement of inner walls and hole walls may closely follow thewalls, with or without layers of fill material shielding the innermostwall to prevent print-through of fiber, e.g., FIG. 12A, 12D, 12F.“Holes” include negative contours and embedded (e.g., overmolded)contours.(2) Reinforcement of outer walls may closely follow the walls, with orwithout layers of fill material shielding the innermost wall to preventprint-through of fiber, e.g., FIGS. 5A-5D “outer” reinforcementformations.(3) Reinforcement may extend along load lines or stress lines, e.g.,FIG. 5C outer reinforcement formation.(4) Reinforcement for tension load purposes may include multiplestraight composite swaths between the sites at which the tension load issupported, e.g., FIG. 12C, 12E, 12F.(5) Reinforcement for torsion, torque, or pressure load purposes mayinclude multiple circular composite swaths along directions of hoopstresses, e.g., FIGS. 12C, 12D.(6) Reinforcement for compression load purposes may include multipleneighboring composite swaths to provide low aspect ratio cross sectionsand/or squat structures, and/or anchors at ½, ⅓ fractional, e.g.harmonic lengths to guard vs. buckling; and/or e.g., more compositeswaths for compression struts than for tension struts.(7) Reinforcement for twisting may include angular cross bracing intriangle or X shapes, e.g., FIG. 12H, or quasi-isotropic sections in 2-6differing dominant angle layers as discussed herein(8) Reinforcement for bending or combination load purposes may includeembedded high moment of inertia (cross section) structures such assandwich panels, tubes, boxes, I-beams, and/or trusses formed fromembedded composite swaths. These may be made in layers spaced from thecentroid of the part cross section, or in outer toolpaths spaced fromthe centroid of the part cross section, depending on the load and theorientation of the part during printing.

Complementary Composite Swath Routing Between Two Layers

FIGS. 13A-13C show complementary paths for reinforcing a hole,distributed between 2, 3, or 4 layers. FIG. 13C shows the reinforcementformations 99Z-4, 99Z-2, mirrored horizontally (HM) and vertically (VM)e.g., in 4 layers, overlaid.

It should be noted that complementary patterns between two layers neednot include a crossing point, jump, or crossing turn to have thebenefits of the use of complementary patterns, or to maintain the amountof stacking at 2 composite swath thicknesses among 2 layers. Thediscussion herein of beneficial stacking of complementary patternsapplies even to layers which do not cross composite swaths within thelayer. For example, FIGS. 13A-13C show superimpositions of thecomplementary paths in 4 alternations over 4 layers. As shown, the holeH0 is reinforced on all sides, with gaps, stress concentrations and/orseams being distributed to different locations among layers (and withinlayers when reinforcement formations are formed within a same layer).Using crossing turns may have various benefits, among them additionalfreedom in determining the location of gaps, starts, stops, and stressconcentrations; additional freedom in orienting gaps, starts, stops, andstress concentrations in different directions and in different forms;and resisting shear and layer and road delamination by creatinginter-layer bonding and shear resistance (e.g., vertical, horizontal,and other binding surfaces). Note a “gap” may be an area within a layerLA_(n) at the beginning, ending, or other location of a fiber orcomposite reinforcement formation that is filled with fill material 18a, e.g., because the shape of the region or contour within which thereinforcement formation is determined may not have sufficient space forfiber to be laid.

Three, Four, and More “Sided” Parts

FIGS. 14A-14C show the principles of complementary toolpaths in atrilaterally symmetric (three sided) context; FIGS. 14D-14E in a foursided context; and FIGS. 14G-14I in a second example of a three sidedcontext.

FIG. 14A shows a single layer of a rotating or three-point contactconnecting plate having three circular holes H_(a), H_(b), H_(c) (herelabeled H9, H10, H11). In FIG. 14A, as shown, contours or regionfollowed by the strategy are coincident with the hole wall but may beoffset from the hole wall (e.g., representing wall thicknesses of fillmaterial 18 a). In FIG. 14A, a reinforcement formation 99T having aspiral tracing strategy is used to follow the three negative contours ofthe hexagonal holes H1, outlined (linking H10, H11, H12). As shown inFIG. 14A, the spiral tracing strategy begins/ends at SP15 the toolpathsurrounding 300 degrees of a round hole H9 and is “anchored” on thatside (i) against the hole wall (ii) by the 300 degree curve about thehole wall and/or (iii) by surrounding composite swaths in the second andsubsequent cycles/loops. As shown, the start/stop of a spiral SP15toolpath do not necessarily start/stop at the same precise location, butmay have additional or added length to surround negative contours orholes so that the lengths of fiber in tension are well anchored. Theswaths 2 c extending between the three holes H10, H11, H12 may beexpected to carry load in a tension mode, and the swaths 2 c closelysurrounding the holes H10, H11, H12 may be expected to reinforce thewalls of the holes H1, H2, in a combined tension-compression mode. FIG.14B shows the superposition of three toolpaths or composite swathdepositions or reinforcement formations 99T of FIG. 14A over one, two,or three layers, rotated from one another or trilaterally mirrored,placing the stress concentrations and/or gaps of the offsets and/orspiral start and end in positions displaced from one another in at leasttwo orthogonal directions (here, substantially the X direction as wellas the Z direction between layers). FIG. 14C shows the furthersuperposition of a circular spiral toolpaths or composite swathdepositions or reinforcement formation 99U over the same layers or anadditional layer, two, or three two layers, carrying or reinforcingversus hoop stresses about the part.

FIG. 14D shows a single layer of a rotating or four-point contactconnecting plate having four circular holes H_(a), H_(b), H_(c), H_(d)(here labeled H16, H17, H18, H19). In FIG. 14D, as shown, contours orregion followed by the strategy are coincident with the hole wall butmay be offset from the hole wall (e.g., representing wall thicknesses offill material 18 a). In FIG. 14D, reinforcement formations 99E and 99F,substantially similar to those depicted in FIGS. 12E and 12F, are usedto follow the four negative contours of the holes, with the offsetstrategy of 99E beginning and ending at OF02, and the spiral strategy of99F beginning and ending at SP05. The reinforcement formations aresubstantially as described with respect to FIGS. 12E and 12F, but areorthogonally arranged about different holes and deposited in one or twolayers. The swaths 2 c extending between the three holes H16, H17, H18,H19 may be expected to carry load in a tension mode, and if printed inthe same layer may create protrusions. FIG. 14E shows the superpositionof four toolpaths or composite swath depositions or reinforcementformations 99E, 99F, 99V, 99U or reinforcement formations 99T of FIG.14A over one, two, three, or four layers, with the further superpositionof two circular spiral toolpaths or composite swath depositions orreinforcement formations 99U, 99V carrying or reinforcing versus hoopstresses about the part.

FIG. 14G shows another example of a three-point contact (in this casetriangular) connecting plate having three circular holes H_(a), H_(b),H_(c). In FIG. 14G, as shown, contours or region followed by thestrategy are coincident with the hole wall but may be offset from thehole wall (e.g., representing wall thicknesses of fill material 18 a).In FIG. 14G, a reinforcement formation 99W having an offset tracingstrategy of an angle offset triangle tangent to the three holes is usedto follow the three negative contours of the hexagonal holes. As shownin FIG. 14G, the spiral offset triangle tracing strategy begins/ends atOF20 and is “anchored” by the 180 degree curve about the hole walland/or by surrounding composite swaths in the second and subsequentcycles/loops. The swaths 2 c extending between the three holes areangled with respect to hoop stress and tension, to be mirrored and formcross-bracing and/or X shapes to resist twisting of the plate of theconnecting plate. FIG. 14H shows the superposition of two toolpaths orcomposite swath depositions or reinforcement formations 99U of FIG. 14Aover one or two layers, left-right mirrored and rotated, placing thestress concentrations and/or gaps of the offsets and/or spiral start andend in positions displaced from one another in at least two orthogonaldirections (here, substantially the X direction as well as the Zdirection between layers). FIG. 14C shows the further superposition ofthe spiral toolpath of FIG. 14A to add further resistance to tension andhoop stresses about the part.

FIG. 15A shows a single layer of a densely filled square plate of fourlong side members, with a hole or negative contour in the middle. InFIG. 15A, as shown, a lengthwise raster fill reinforcement formation 99Xsurrounds the contour or region in the middle. There are many turns inthe raster pattern, and two gaps GAP1 and GAP2 (which may also be stressconcentrations, starts, or stops are formed. GAP1 is formed where thepattern changes regional groups, and GAP 2 is formed at the end of thecomposite swath 2 c. These gaps may also occur if the composite swath 2c length is not perfectly predicted or measured. Within the layer, thegaps may be filled with (i) fill material 18 a, (ii) lengths ofcomposite swath 2 c which do not continue the raster fill (e.g., gapfilling patterns, which may be concentric, wall or region following),(iii) and/or with overlapping composite swath 2 c or protrusion PR. E.g.in order to fill the GAP1 or GAP2 in FIG. 15A with overlapping compositeswath 2 c, each raster pattern would be widened to overlap (e.g., FIG.15B, wherein the gaps are closed with protrusions PR, which may bevaried in position among layers as discussed herein). In FIG. 15B, twosuperimposed reinforcement formations 99X, 99X layers are shown, wherethe reinforcement formation 99X is rotated by 90 degrees, optionally inthe subsequent layer. The reinforcement formation 99X may be rotated at90 degrees, then again, in an additional two layers to continue tochange the position of the gap, stress concentration, starts, or stops.Optionally, the pattern is rotated by 45 degrees in some interveninglayers.

Sparse Fill in or with Complementary Formations

As shown in FIGS. 16A-16D, complementary formations can be used insparse fill approaches, e.g., generally honeycombs and tessellations forfilling internal volumes of a part 14. In this case, as describedherein, some approaches are suitable for honeycomb regions of layersLA_(n), LA_(n+1), LA_(n+2), etc. including either or both ofconsolidated composite swaths 2 c and fill material 18 a. In the case ofconsolidated composite swaths 2 c, more attention may be given tostacking of protrusions from an underlying layers LA_(n) to layer(s)above LA_(n+1), etc.

Each of FIGS. 16A-16D again shows reinforcement formations 99 withinsingle or multiple layers LA_(n), LA_(n+1), LA_(n+2), etc.

The controller 20 of the printer 1000, may, as described herein,supplying a multi-strand core reinforced filament 2 including a flowablematrix material 4 a and a plurality of substantially continuousreinforcing strands 6 a of a material having a tensile strength ofgreater than 300 MPa. The substantially continuous reinforcing strands 6a extend in a direction parallel to a length of the filament. As shownin FIG. 16A, within a first layer LA_(n), the printer 1000 deposits afirst consolidated composite swath 2 c of a height less than ½ the widthof the filament 2 in a first reinforcement formation 99Z1 (although theprinter 1000 could begin with any of 99Z1, 99Z2, 99Z3) including a firstplurality of parallel lengths each extending in a first direction byflowing the matrix material 4 a and applying an ironing force thatspreads the reinforcing strands 6 a within the filament against adeposition surface 14 or 2 d. In the case of FIGS. 16A-16D, the parallellengths of reinforcement formations 99Z1, 99Z2, 99Z3, 99Z3-1 areattached to one another by further lengths following an outline, offset,or wall of the part 14, but this is optional. In this case, the firstformation 99Z1 deposited is a reference formation, and the remainingformations in the sparse fill set are angled with reference to theparallel lengths of the first formation 99Z1.

Optionally, within the same first layer LA_(n), the printer 1000deposits a second consolidated composite swath 2 c of a height less than½ the width of the filament 2 in a second reinforcement formation 99Z2including a second plurality of parallel lengths each extending a seconddirection angled from the first direction by sixty degrees, by flowingthe matrix material 4 a and applying an ironing force to spread thereinforcing strands 6 a within the filament 2 against the firstplurality of parallel lengths of the first consolidated composite swath2 c of the formation 99Z1. Subsequently, in a second layer LA_(n+1)above the first layer LA_(n), the printer 1000 may deposit a thirdconsolidated composite swath 2 c of a height less than ½ the width ofthe filament 2 in a third reinforcement formation 99Z3 including a thirdplurality of parallel lengths each extending a third direction angledfrom the first and second directions by sixty degrees, by flowing thematrix material 4 a and applying an ironing force to spread thereinforcing strands 6 a within the filament 2 against both the first andsecond pluralities of parallel lengths of the first and secondconsolidated composite swaths 2 c, 2 c of the formations 99Z1, 99Z2. Theangle from the first formation of the second, third formations mayalternatively be 120 degrees, 90 degrees, or other angles which divideevenly into 360 degrees.

Further optionally, as shown in FIG. 16B, the printer 1000 for maydeposit the third consolidated composite swath 2 c of the thirdformation 99Z3 is deposited with the third plurality of parallel lengthseach crossing (e.g., triangle honeycomb, tessellation, or network) anintersection of the first and second consolidated composite swaths 2 c,2 c of the first and second formations 99Z1, 99Z2. Alternatively or inaddition, as shown in FIG. 16C, the printer 1000 for may deposit thethird consolidated composite swath 2 c of the third formation 99Z3 isdeposited with the third plurality of parallel lengths each offset(e.g., Star-of-David honeycomb, tessellation, or network) from anintersection of the first and second consolidated composite swaths 2 c,2 c of the first and second formations 99Z1, 99Z2.

Alternatively, even in the case of fill material 18 a only, thecontroller 20 of the printer 1000, may, supplying a filament including aflowable polymer material, and within a first layer LA_(n), deposit rowsof the flowable polymer material 18 a in a first reinforcement formation99Z1 including a first plurality of parallel lengths each extending in afirst direction by flowing the flowable polymer material 18 a against adeposition surface 14, and within the same first layer LA_(n), depositrows of the flowable polymer material 18 a in a second reinforcementformation 99Z2 including a second plurality of parallel lengths eachextending in a second direction angled from the first direction by sixtydegrees, by flowing the flowable polymer material 18 a against thedeposition surface (at least in part the prior bead from formation 99Z1)and to thin out when the second plurality of parallel lengths crossesthe first rows of the flowable polymer material. Within the same firstlayer LA_(n), the controller 20 may deposit rows of the flowable polymermaterial 18 a in a third reinforcement formation including a thirdplurality of parallel lengths each extending in a third direction angledfrom the first and second directions by sixty degrees, by flowing thematrix material against the first rows of the flowable polymer materialand to thin out when the third plurality of parallel lengths crosses thefirst and second pluralities of parallel lengths of the first two rowsof the flowable polymer material.

This technique for fill material 18 also applies to composite swaths,e.g., in the case where supplying a filament further comprises supplyinga multi-strand core reinforced filament 2 including a flowable polymermatrix material 4 a and a plurality of substantially continuousreinforcing strands 6 a of a material having a tensile strength ofgreater than 300 MPa as discussed herein, where each row of flowablepolymer material is deposited as a consolidated composite swath 2 c asdiscussed herein, and advantageously as the third plurality of parallellengths is deposited with each parallel length offset from anintersection of the first and second consolidated parallel lengths.

The interaction of the reinforcement formations may be implemented onthe slicer or toolpath planner. In this case, a computer or workstationexecutes instructions for generating three-dimensional toolpathinstructions for a three dimensional printer. The computer receives athree-dimensional geometry such as a solid model, NURBS model, mesh orSTL file. The computer slices the three-dimensional geometry into layersLA₁ . . . LA_(m), and generates toolpath instructions to depositconsolidated composite swaths 2 c by ironing strand reinforced compositefilament 2 to form consolidated composite swaths 2 c having reinforcingstrands 6 a spread out against a surface 14 or 2 d. The computergenerates toolpath instructions to deposit a first consolidatedcomposite swath 2 c according to a first single layer toolpath orreinforcement formation 99Z1 within a first layer of the layers LA₁ . .. LA_(m); (note a layer designated LA₁ herein need not be the firstlayer of the part; LA₁ is rather the first layer of the set of layersunder discussion, which may begin or end anywhere within the part 14.The computer may generate toolpath instructions to deposit a secondconsolidated composite swath 2 c according to a second single layertoolpath or reinforcement formation 99Z2 within the same first layer,the second consolidated composite swath having a crossing point with thefirst consolidated composite swath within the same first layer LA₁, andgenerate toolpath instructions to iron the second consolidated compositeswath 2 c to spread against the first consolidated composite swath 2 cwithin the same first layer LA₁.

With reference to FIG. 16A and the preceding discussion, all ofreinforcement formations 99Z1-99Z3, together forming a honeycomb, may bedeposited in one layer LA_(n). If all three reinforcement formations99Z1-99Z3 are formed from composite swaths 2 c and the pattern99Z1-99Z2-99Z3 of FIG. 16B is constructed, each intersection of threecomposite swaths will form a double-height protrusion which will tend toaccumulate, and the neighboring layer LA_(n+1) may be deposited withonly fill material 18 a (in the same reinforcement formations).Alternatively, the double-height protrusion that is an intersection ofthree paths 2 c may be smaller than other protrusions as theintersection is entirely surrounded by air space into which the paths 2c may flatten. Alternatively, if all three reinforcement formations99Z1-99Z3 are formed from composite swaths 2 c and the pattern99Z1-99Z2-99Z3-1 of FIG. 16C is constructed, all intersections are aprotrusion of only one additional layer of swath 2 c-2. Again, theneighboring layer LA_(n+1) of honeycomb may be deposited with only fillmaterial or again with fiber or composite swaths 2 c, although in thecase of the reinforcement formation set of FIG. 16C, the accumulation ofoverlaps is less than with FIG. 16B.

Further, with reference to FIG. 16D, the reinforcement formations 99Z1,99Z2, 99Z3 may be arranged in permutation pairs per layer. E.g. if thefirst pair of reinforcement formations 99Z1, 99Z2 is printed in a firstlayer LA_(n), an array of protrusions PR occurs at the intersections ofthe reinforcement formations. If the second pair of reinforcementformations 99Z2, 99Z1 is printed in a first layer LA_(n+1), a secondarray of protrusions PR occurring at the intersections of thereinforcement formations are in a different coordinate locations(without interfering with those from the first pair), and if the thirdpair of reinforcement formations 99Z2, 99Z3 is printed in a first layerLA_(n+2), a third array of protrusions PR occurs at the intersections ofthe reinforcement formations in this layer LA_(n+2), and different fromboth of the first two layers LA_(n), LA_(n+1). Accordingly, if thesethree layers LA_(n), LA_(n+1), LA_(n+2) as described are repeatedly laidnext to one another, no more than one protrusion PR height is generatedper layer. With this strategy, the third complementary pattern (e.g.,for 99Z1, 99Z3 pair, the third complementary pattern would be 99Z2) maybe printed with fill material 18 a in the same layer.

Extrusion Toolpaths and/or Extrudates

In general, in the “FFF” or “FDM” extrusion method of additivemanufacturing, extrusion beads in adjacent layers LA_(n), LA_(n+1) maybe arranged to run either parallel or transverse to one another, withoutcrossing while within a layer. A “retract” may be performed in thefilament feed path to stop nozzle flow and move from one isolated areato another to restart extrusion, but the active printing beads tend toremain uncrossed. This is reasonable, because continuing to extrudewhile crossing a previously printed bead may cause extrudate to jet outhorizontally and unpredictably as the nozzle is partially blocked.Additionally, any time spent extruding with a blocked nozzle reduces theamount of active deposition of extrusion. Slicing software generallyavoids creating extrusion toolpaths which cross one another.

However, in the FFF printer discussed herein, extrusion toolpaths maycross one another in the same manner as described with respect to corereinforced fiber toolpaths, partially enabled by a fast-responseclutching in the filament supply for the extrusion head 18, e.g., a lowmotor current or other slippable drive. In such a case, crossingextrusion toolpaths should cross at a high angle (e.g., from 45-90degrees) and/or limited to short periods of time or narrow existingbeads (e.g., for 1/10 to 1/100 of a second, e.g., for a printingextrusion speed of 300 mm/s, crossing no more than 1 mm of previouslysolidified extrudate, and preferably ¼ to ½ mm of solidified extrudate).This is particularly advantageous in the case of honeycomb fills ofpatterned lines (e.g., triangular tessellation, e.g., of 60-60-60 degreecrossing straight paths, either with all paths intersecting (e.g.,triangular honeycomb or two paths intersecting with one path offset(e.g., Star of David network or honeycomb).

Generally, even the fast-response buffered crossing of a newly extrudedbead or road of fill material 18 a across a previously printed extrusionbead or toolpath may not change the layer height of the current layerLA_(n) either on top of the solidified bead crossed or in the currentlydeposited row, i.e., neat plastic does not generally verticallyaccumulate as beads are crossed. Rather, fluidized fill material 18 atends to find a least resistance direction to escape horizontally ordownward when the extrusion nozzle 18 is blocked by a previouslydeposited bead.

A schematic representation of a composite structure is depicted in FIG.17 which shows a sandwich panel composite part. The top section 1900,and bottom section 1902, are printed using a continuous core reinforcedfilament to form relatively solid portions. In contrast, the middlesection 1904 may be printed such that it has different properties thanthe top section 1900 and the bottom section 1902. For example the middlesection 1904 may include multiple layers printed in a honeycomb patternusing a continuous core reinforced filament, a pure resin, or even athree dimensionally printed foaming material. This enables theproduction of a composite part including a lower density core using athree dimensional printer. Other composite structures that are noteasily manufactured using typical three dimensional printing processesmay also be manufactured using the currently described systems,materials, and methods.

In addition to using the continuous core reinforced filaments to formvarious composite structures with properties in desired directions usingthe fiber orientation, in some embodiments it is desirable to provideadditional strength in directions other than the fiber direction. Forexample, the continuous core reinforced filaments might includeadditional composite materials to enhance the overall strength of thematerial or a strength of the material in a direction other than thedirection of the fiber core. For example, FIG. 18 shows a scanningelectron microscope image of a carbon fiber core material 2000 thatincludes substantially perpendicularly loaded carbon nanotubes 2002.Without wishing to be bound by theory, loading substantiallyperpendicular small fiber members on the core increases the shearstrength of the composite, and advantageously increases the strength ofthe resulting part in a direction substantially perpendicular to thefiber direction. Such an embodiment may help to reduce the propensity ofa part to delaminate along a given layer.

FIGS. 19A-19C depict various parts formed using the printer head(s)depicted in FIGS. 1A-1C and/or 2A-2G. FIG. 19A shows a part including aplurality of sections 1322 deposited as two dimensional layers in the XYplane. Sections 1324 and 1326 are subsequently deposited in the ZY planeto give the part increased strength in the Z direction. FIG. 19B show arelated method of shell printing, where layers 1328 and 1330 are formedin the XY plane and are overlaid with shells 1332 and 1334 which extendin both the XY and ZY planes. As depicted in the figure, the shells 1332and 1334 may either completely overlap the underlying core formed fromlayers 1328 and 1330, see portion 1336, or one or more of the shells mayonly overly a portion of the underlying core. For example, in portion1338 shell 1332 overlies both layers 1328 and 1330. However, shell 1334does not completely overlap the layer 1328 and creates a steppedconstruction as depicted in the figure. FIG. 19C shows an alternativeembodiment where a support material 1340 is added to raise the partrelative to a build platen, or other supporting surface, such that thepivoting head of the three dimensional printer has clearance between thepart and the supporting surface to enable the deposition of the shell1342 onto the underlying layers 1344 of the part core.

The above described printer head may also be used to form a part withdiscrete subsections including different orientations of a continuouscore reinforced filament. The orientation of the continuous corereinforced filament in one subsection may be substantially in the XYdirection, while the direction in another subsection may be in the XZ orYZ direction.

The path planning and printing processes may utilize a fill pattern thatuses high-strength composite material in selected areas and fillermaterial (e.g., less strong composite or pure resin such as nylon) inother locations, see FIGS. 19D-19G, which depict stacks of layers incross section. As discussed with reference to the sandwich panel globalor region rule, in some cases, reinforcement is conducted by identifyingan internal volume or volumes in the shape of simplified beams or panel,e.g., an interior prism or volume spanning and extending beyond bendingload and/or support points. In addition, the part may be oriented duringplanning for deposition such that layers within the volume span theanticipated load and/or support points. Fiber may be fiber added withinthe interior prism volume remote from a centroid of a cross section ofthe volume, to increase effective moment of inertia (particularly forbending or compression loads). Fibers may be deposited in multipleadjacent bonded ranks and/or layers, to increase fiber rank interactionand reinforcement of neighbors (particularly for compression and tensionloads). Through holes or mounts through which or into which load membersare expected to be inserted may each be smoothly looped by fiber,optionally directly at the wall of such mount (particularly for tensionand torsion loads, looping may permit fewer stress concentrations andthe transmission of tension through smooth paths).

Especially for beam and panel bending, the strength to weightperformance of a beam is optimized by placing fiber ranks as far aspossible (i.e., at the farthest position both within the part and thatdoes not violating any higher priority rules in effect at the boundaryof the part) from the centroid of a cross-section to increase effectivemoment of inertia. A part formed completely from the fill material 1350is depicted in FIG. 19D. In FIG. 19E, a composite material 1352 isdeposited at the radially outward most portions of the part andextending inwards for a desired distance to provide a desired increasein stiffness and strength. The remaining portion of the part is formedwith the fill material 1350. A user may extend the use of compositeversus filler either more or less from the various corners of the partas illustrated by the series of figures FIGS. 19D-19G. For example, acontrol algorithm controlled by controller 20 may use a concentric fillpattern that traces the outside corners and wall sections of the part,for a specified number of concentric infill passes, the remainder of thepart may then be filled using a desired fill material.

FIGS. 19H-19J depict further parts formed using the printer head(s)depicted in FIGS. 1A-1C and/or 2A-2G.

Where FIGS. 19E through 19G do not expressly show outer walls of thepart formed from fill material 1350 (e.g., the parts in FIGS. 19E-19Gmay have outer wall(s) of fill material 1350 or outer walls of compositematerial 1352), FIGS. 19H through 19J show cross sections of parts withthe outer wall 1350-OW specifically shown.

Specifically, in FIG. 19H, a part is built up from the lowest layer ordown from the highest layer, depending on the printing type or approach.In FIG. 19H, an outer layer of fill material 1350 is formed by a floorlayer of fill material 1350 (the outer layer may be 1-3 or moresuccessive floor layers). As in FIGS. 19E-19G, an internal sandwichpanel is built of composite material 1352, in this case as twoquasi-isotropic sets 1352-QI separated by infill material 1350-IF. Inthis case, a quasi-isotropic set 1352-QI is formed by four parallelshells or layers of anisotropic fill or composite fiber swaths, in whichthe dominant direction of the fiber swaths is rotated by 45 degrees (ina known manner for quasi-isotropic laminates of four layers) betweeneach layer (as noted herein, a quasi-isotropic set of layers or shellstends be composed of 3 or more layers, the layers together having asubstantially isotropic stiffness behavior as a laminate). As discussed,the quasi-isotropic sets 1352-QI are deposited adjacent or proximate thetop and bottom of the part to provide a higher moment of inertia andbending stiffness. The quasi-isotropic sets 1352-QI also providetwisting or torsion stiffness. As shown, in contrast to FIGS. 19E-19G,in FIG. 19H outer walls 1350-OW (including 1-3 or more beads ofisotropic fill material) optionally surround the sets 1352-QI ofquasi-isotropic layers so that the outer surface of the part is fillmaterial 1352.

Further in contrast to FIGS. 19E-19G, the middle fill material section1350-IF is surrounded by outer concentrically deposited anisotropiccomposite fiber swaths 1352-CON (e.g., as shown in single layer form inFIG. 10F, 10G, or 101; or layers L04.2 or L04.1 of FIG. 11A). Eachconcentric fiber swath fill section 1352-CON may be any number ofconcentric loops, e.g., 1-10 or higher. Again, optionally, outer walls1350-OW (including 1-3 or more beads of isotropic fill material)optionally surround the sets 1352-CON of quasi-isotropic layers and fillmaterial 1352 so that the outer surface of the part is fill material1352. In addition, the upper quasi-isotropic layer set 1352-QI isadditionally covered by a roof fill of fill material 1350-R (again, 1-3or more layers of isotropic fill material 1350). In this manner, theentire outer surface of the part is optionally sheathed in fill material1352, but immediately adjacent the fill material 1352 outer surfaces anddisplaced outwardly from a centroid of the part, composite material 1352is deposited to increase effective moment of inertia in eitheranisotropically deposited quasi-isotropic sets 1352-QI, and/orconcentrically deposited layers 1352-CON. Accordingly, outer contours,perimeters, roofs, and floors of the 3D geometry, whether formed fromlayers or shells of the 3D printing process or formed from walls, beads,or swaths within a respective layer or shell of the 3D printing process,are surrounded by an inner shell of composite material 1352. It shouldbe further noted that one exemplary fill approach for the concentricallydeposited outer layers 1352-CON is concentric loops, spirals, or offsetsstarting at an outer region perimeter or contour and spiraling inward1352-O.CON (outer concentric fill).

In a variation of the part of FIG. 19H of a part having a through-holeTH-H as shown in FIG. 19I, the general approach of FIG. 19H may befollowed. In contrast, in FIG. 19I, the negative contours or holes foundin each layer having anisotropically deposited and/or oriented fiberfill, quasi-isotropic sets of layers 1350-R, and also found in eachlayer having anisotropically deposited and/or oriented fiber fill, outerconcentric layers 1352-CON, are surrounded by these respective fills aswell as isotropic, resin or fill material infill 1350-F. However,immediately adjacent the negative contour, a reinforcing column formedfrom an optional inner wall of isotropic, resin or fill material 1350-IWand an inner wall of anisotropically deposited and/or oriented fiberfill, inner fill concentric layers 1352-I.CON (e.g., a tube ofconcentric fiber and/or concentric fill material surrounding the throughhole TH-H). A non-through, terminating hole may be similarly structured(e.g., the sides of the hole being similarly concentric inner fill offiber 1352-I.CON and/or inner wall resin or fill material fill 1350-IW,and the bottom of the hole being terminated with, as permitting, aquasi-isotropic set 1352-QI and/or a roof layer 1350-R). As shown, thereinforcing column may extend through the infill 1350-IF, the outerconcentrically reinforced layers 1352-O.CON or 1352-CON, as well as thequasi-isotropic sets of layers 1352-QI, such that two or three or moreregions, fill patterns, or toolpath generation approaches are used inthese layers, either in exclusive regions or in overlapping regions witha set priority among generation rules. As an example, a layer depictedin FIG. 10J includes an outer concentric fiber fill surrounding both ofan anisotropically deposited and oriented infill IF that is one layer ofa quasi-isotropic set, as well as an inner concentric fiber fillsurrounding a negative contour. The reinforcing column formed from innerwall resin fill 1350-IW and/or inner concentric fiber fill 1352-I.CONmay surround more than one hole or negative contour in each layer, e.g.,in a manner as shown in FIGS. 12A-12J (two holes) or 14A (three holes),or may be a reinforcing structure distributed among different layers ina set or laminate (e.g., as shown in FIGS. 13A-13C). In this manner,negative contours, through-holes, and similar structures, whether formedfrom layers or shells of the 3D printing process or formed as wallswithin a layer or shell of the 3D printing process, also are surroundedby an inner shell of composite material.

In a further variation of the part of FIG. 19H of a part having aninternally dense fiber infill pattern, as shown in FIG. 19J, the generalapproach of FIG. 19H may again be followed. In contrast, in FIG. 19J, amatrix or cellular arrangement of concentrically filled anisotropicmaterial walls (of anisotropically deposited and oriented fibermaterial) 1352-CLW is arranged within the part to provide increasingfiber density and/or stiffness and/or crushing resistance. The patternof cell walls 1352-CLW may be a honeycomb, for example as discussed withreference to FIGS. 16A-16D, e.g., formed from reinforcement formations99Z1-4. Further, the pattern of cell walls of anisotropically depositedand oriented fiber material 1352-CLW may be formed by crossing ornon-crossing outer concentric or inner concentric fills 1352-O.CON or1352-I.CON. The pattern of cell walls of anisotropically deposited andoriented fiber material 1352-CLW may be a mirroring, repeating,orthogonally varying, or complementary arrangement as shown, e.g., inFIGS. 14G-14I and/or FIGS. 15A, 15B. The cells are filled with infillmaterial 1350-IF, in a dense or sparse arrangement. Additionally incontrast, in FIG. 19J, one or more intervening sets of quasi-isotropicfill 1352-QI (of anisotropically deposited and oriented fiber material)may be formed as an inner wafer other than at the top and bottom regionsremote from the centroid. As shown in FIG. 19J, in contrast to FIG. 19H,the one or more intervening sets of quasi-isotropic fill 1352-QI (ofanisotropically deposited and oriented fiber material) may be furthersurrounded by an outer concentric fill 1352-O.CON (in order to provide aconsistent outer shell) or may instead fill a layer to an outer wall ofresin material 1350-OW (as with the upper and lower sets ofquasi-isotropic fill 1352-QI.

It should be further noted that the structures of FIGS. 19I and 19J maybe combined by using exclusive regions or regions having a priorityamong them, e.g., through-holes TH-H may penetrate through or partiallythrough a matrix or cellular arrangement of fiber fills 1352-CLW and/or1352-QI combined with fill material 1350-IF and be nonethelesssurrounded by wall-reinforcing tubes of fiber and/or fill material,e.g., as shown in FIG. 10J.

As shown in each of FIGS. 19H-19J, at least one (e.g., 1-3 or more) rooflayer of resin or isotropic material or infill material 1350-R, solid,filled or densely filled in ox-row or other packed fashion, may beprinted above a set of resin or fill material infill 1350-IF. The infill1350-IF may in some cases be a sparse honeycomb pattern, and the solid,filled or densely filled roof layer(s) 1350-R provide a complete shellor layer surface upon which the anisotropic fiber swaths may becompressed and fused.

As shown in FIGS. 19A-19J, the three-dimensional geometry of the partsshown in FIGS. 19A-19J may be sliced into shells or layers as describedherein with reference to FIGS. 4-10. For each of a set of shells orlayers defining a portion of a 3D printed part, first isotropic filltool paths such as 1322, 1328, 1330, 1344, 1350, 1350-R, 1350-OW, and/or1350-IW may be generated for controlling an isotropic solidifying head(e.g., head 18 or 1800 or 1616) to solidify, along the isotropic filltool paths, a substantially isotropic fill material such (e.g., material18 a or 1604). For each of an anisotropic fill subset of the set ofshells or layers defining the portion of the 3D printed part (e.g., thedifferent fiber fills throughout a part), first anisotropic fill toolpaths (e.g., 1352-QI or 1352-O.CON or 1352 I.CON) may be generated forcontrolling an anisotropic solidifying head to solidify, along theanisotropic tool paths, a substantially anisotropic fill material havingan anisotropic characteristic oriented relative to a trajectory of theanisotropic fill tool path. As shown with reference to FIGS. 10A-10K,particularly 10E-10K, from among the set of shells or layers definingthe portion of the 3D printed part, a selection of an editing subset ofshells or layers may be received, the editing subset including at leastpart of the anisotropic fill subset. For each shell or layer of theediting subset, one of second isotropic fill toolpaths different fromthe first isotropic fill toolpaths and second anisotropic fill toolpathsdifferent from the first anisotropic fill toolpaths may be regenerated.

Similarly, a printer for additive manufacturing of a part may include ananisotropic solidifying head (e.g., head 10, or 199) that solidifies,along anisotropic fill toolpaths, fiber swaths from a supply ofanisotropic fiber reinforced material including a plurality of fiberstrands extending continuously within a matrix material, the fiberswaths having an anisotropic characteristic oriented relative to atrajectory of the anisotropic fill tool paths. An isotropic solidifyinghead (e.g., head 18 or 1800 or 1616) may solidify, along isotropic filltoolpaths, a substantially isotropic material from a supply ofsolidifiable isotropic material. A motorized drive as shown in FIGS. 1and 2 (all suffixes inclusive) may relatively move at least theanisotropic deposition head and a build plate supporting a 3D printedpart in three or more degrees of freedom. A controller 20 may beoperatively connected to and configured to control the motorized drive,the anisotropic solidifying head and the isotropic solidifying head, andmay control these to build the 3D printed part by solidifying theisotropic material along the isotropic fill tool paths, and/orsolidifying the anisotropic fill material in fiber swaths tracking anon-concentric set (e.g., quasi-isotropic set 1352-QI, or any of thenon-concentric complementary sets in FIGS. 12-14, all suffixesinclusive) of the of anisotropic fill tool paths for at least a firstsequence of parallel shells. Further, the controller may control theseelements to solidify the anisotropic fill material in fiber swathstracking an outer concentric set (e.g., 1352-CON, or any of theconcentric layer types shown in FIGS. 12-14, all suffixes inclusive) ofanisotropic fill tool paths for at least a second sequence of parallelshells. Each of the non-concentric set and the outer concentric set ofanisotropic tool paths may be located at least partially radiallyoutward from the centroid of the 3D printed part, as shown in FIGS.19H-19H.

As shown in FIG. 20, the controller 20 of the printer 1000 may controlthe actuators and heaters such that depositing the first consolidatedcomposite swath 2 c and the second consolidated composite swath 2 c as acontinuous composite swath 2 c spanning (e.g., via inter-layercontinuous traverse SP30-A, SP30-B) two shells LA_(n), LA_(n+1) of anadditive manufacturing process.

Section headings used herein are dependent upon following content whichthey describe, and can only broaden the content described.

Terminology

A “composite swath” or “composite swath” may refer to a depositedfiber-reinforced composite filament, having been compressed,consolidated and widened by ironing during deposition. Extending withinthe composite swath are a plurality of individual fibers, from 50-5000,preferably 100-2000, within a matrix material.

A “multi-swath track” may refer to a set of parallel swaths thatgenerally follow parallel paths, although individual swaths may deviateto avoid obstacles or achieve reinforcement goals.

A “fold” may refer to a composite swath which folds, twists, or bunchesover itself along a curved segment of composite swath (such as acorner). A “fold” is not limited to sheet-like or tape-like folds, butincludes path changes in which different fibers within the compositeswath may cleanly switch sides of a swath, but may also cross, twist, orbunch along the curved or angled segment (such as a corner).

“Fill material” includes material that may be deposited in substantiallyhomogenous form as extrudate, fluid, or powder material, and issolidified, e.g., by hardening, crystallizing, transition to glass, orcuring, as opposed to the core reinforced filament discussed herein thatis deposited as embedded and fused composite swaths, which is depositedin a highly anisotropic, continuous form. “Substantially homogenous”includes powders, fluids, blends, dispersions, colloids, suspensions andmixtures, as well as chopped fiber reinforced materials.

“Honeycomb” includes any regular or repeatable tessellation for sparsefill of an area (and thereby of a volume as layers are stacked),including three-sided, six-sided, four-sided, complementary shape (e.g.,hexagons combined with triangles) interlocking shape, or cellular.

A “Negative contour” and “hole” are used herein interchangeably.However, either word may also mean an embedded contour (e.g., anembedded material or object) or a moldover contour (e.g., a secondobject with surfaces intruding into the layer).

“Outwardly spiraling” or “outwardly offsetting” meaning includes that aprogressive tracing, outlining, or encircling is determined withreference to an innermost, generally negative or reference contour, notnecessarily that the composite swath mush begin next to that contour andbe built toward an outer perimeter. Once the toolpath is determined, itmay be laid in either direction. Similarly, “inwardly spiraling” or“inwardly offsetting” means that the progressive tracing is determinedwith reference to an outer, generally positive contour.

“3D printer” meaning includes discrete printers and/or toolheadaccessories to manufacturing machinery which carry out an additivemanufacturing sub-process within a larger process. A 3D printer iscontrolled by a motion controller 20 which interprets dedicated G-code(toolpath instructions) and drives various actuators of the 3D printerin accordance with the G-code.

“Extrusion” may mean a process in which a stock material is pressedthrough a die to take on a specific shape of a lower cross-sectionalarea than the stock material. Fused Filament Fabrication (“FFF”),sometimes called Fused Deposition Manufacturing (“FDM”), is an extrusionprocess. Similarly, “extrusion nozzle” shall mean a device designed tocontrol the direction or characteristics of an extrusion fluid flow,especially to increase velocity and/or restrict cross-sectional area, asthe fluid flow exits (or enters) an enclosed chamber.

A “conduit nozzle” may mean a terminal printing head, in which unlike aFFF nozzle, there is no significant back pressure, or additionalvelocity created in the printing material, and the cross sectional areaof the printing material, including the matrix and the embeddedfiber(s), remains substantially similar throughout the process (even asdeposited in bonded ranks to the part).

“Deposition head” may include extrusion nozzles, conduit nozzles, and/orhybrid nozzles. “Solidifying head” may include the same, as well aslaser melting and solidifying, laser curing, energy curing. A materialneed not be liquified to be solidified, it may be cured, sintered, orthe like.

“Filament” generally may refer to the entire cross-sectional area of an(e.g., spooled) build material, and “strand” shall mean individualfibers that are, for example, embedded in a matrix, together forming anentire composite “filament”.

“Alternating”, with respect to reinforcement regions, generally means inany regular, random, or semi-random strategy, unless the pattern isdescribed, specified, or required by circumstances, for distributingdifferent formations within or among layers. E.g., simple alternation(ABABAB), repeating alternation (AABBAABB), pattern alternation(ABCD-ABCD), randomized repeating groups (ABCD-CBDA-CDAB), true randomselection (ACBADBCABDCD), etc.

“Shell” and “layer” are used in many cases interchangeably, a “layer”being one or both of a subset of a “shell” (e.g., a layer is an 2.5Dlimited version of a shell, a lamina extending in any direction in 3Dspace) or superset of a “shell” (e.g., a shell is a layer wrapped arounda 3D surface). Shells or layers may be nested (within each other) and/orparallel (offset from one another) or both. Shells or layers aredeposited as 2.5D successive surfaces with 3 degrees of freedom (whichmay be Cartesian, polar, or expressed “delta”); and as 3D successivesurfaces with 4-6 or more degrees of freedom. Layer adjacency may bedesignated using descriptive notations “LA₁”, “LA₂” or LA_(n),LA_(n+1)”, etc., without necessarily specifying unique or non-uniquelayers. “LA₁” may indicate the view shows a single layer, “LA₂”indicating a second layer, and “LA₁, LA₂” indicating two layerssuperimposed or with contents of each layer visible. For example, in atop down view, either of “LA₁, LA₂, LA₃” or “LA_(n), LA_(n+1), LA_(n+2)”may indicate that three layers or shells are shown superimposed. “LA₁,LA₂ . . . LA_(m),” may indicate an arbitrary number of adjacent layers(e.g., m may be 2, 10, 100, 1000, or 10000 layers).

Some representative Ultimate/Tensile Strength and Tensile/Young'sModulus values for reinforcing fibers, core reinforced fiber matrixmaterials, fill materials, and comparative materials are as follows:

Ultimate Strength Young/Tensile MATERIAL MPa Modulus GPa reinforcingstrands—UHMWPE— 2300-3500 0.7 Dyneema, Spectra reinforcingstrands—Aramid or Aramid 2000-2500   70.5-112.4, Fiber—Kevlar, Nomex,Twaron 130-179 reinforcing strands—Carbon Fiber 4000-4500 300-400reinforcing strands—Glass Fiber (E, R, S) 3500-4800 70-90 reinforcingstrands—Basalt fiber 1300-1500  90-110 Carbon Fiber reinforced plastic(70/30 1600 170-200 fiber/matrix, unidirectional, along grain)Glass-reinforced plastic (70/30 by weight 900 40-50 fiber/matrix,unidirectional, along grain) Steel & alloys ASTM A36 350-450 200Aluminum & alloys 250-500 65-80 matrix, fill material, solidifiable12-30 3.5 material—Epoxy matrix, fill material, solidifiable 70-90 2-4material—Nylon

What is claimed is:
 1. A 3D printer for additive manufacturing of apart, comprising: an anisotropic solidifying head that solidifies, alonganisotropic fill toolpaths, fiber swaths from a supply of anisotropicfiber reinforced material including a plurality of fiber strandsextending continuously within a matrix material, the fiber swaths havingan anisotropic characteristic oriented relative to a trajectory of theanisotropic fill tool paths; an isotropic solidifying head thatsolidifies, along isotropic fill toolpaths, a substantially isotropicmaterial from a supply of solidifiable isotropic material; a motorizeddrive for relatively moving at least the anisotropic solidifying headand a build plate supporting a 3D printed part in at least three degreesof freedom, and a controller, wherein the controller is configured tocontrol the motorized drive, the anisotropic solidifying head and theisotropic solidifying head, to which the controller is operativelyconnected, to build the 3D printed part by: solidifying the isotropicmaterial along the isotropic fill tool paths, solidifying theanisotropic fill material in fiber swaths tracking a non-concentric setof anisotropic fill tool paths for at least a first sequence of parallelshells, solidifying the anisotropic fill material in fiber swathstracking an outer concentric set of anisotropic fill tool paths for atleast a second sequence of parallel shells, each of the non-concentricset and the outer concentric set of anisotropic tool paths being locatedat least partially radially outward from a centroid of the 3D printedpart.
 2. The 3D printer according to claim 1, wherein the non-concentricset of anisotropic tool-paths includes a quasi-isotropic set ofanisotropic fill tool paths forming a laminate having a partiallyisotropic in-shell behavior among three or more shells, and wherein thecontroller is further configured to control the motorized drive, theanisotropic deposition head and the isotropic solidifying head to buildthe 3D printed part by solidifying the anisotropic fill material infiber swaths tracking a quasi-isotropic set of anisotropic fill toolpaths for at least the first sequence of parallel shells.
 3. The 3Dprinter according to claim 2, wherein the controller is furtherconfigured to control the motorized drive, the anisotropic depositionhead and the isotropic solidifying head to build the 3D printed part bysolidifying the anisotropic fill material in fiber swaths tracking aquasi-isotropic set of anisotropic fill tool paths for at least anadditional sequence of parallel shells separated from the first sequenceof parallel shells by a plurality of shells each including isotropicfill material.
 4. The 3D printer according to claim 1, wherein thenon-concentric set of anisotropic tool-paths includes a set ofcomplementary anisotropic fill tool paths of substantially similar arealdistribution, the complementary anisotropic fill tool paths forming alaminate having a combined in-shell behavior among two or more shells,wherein the controller is further configured to control the motorizeddrive, the anisotropic deposition head and the isotropic solidifyinghead to build the 3D printed part by solidifying the anisotropic fillmaterial in fiber swaths tracking the set of complementary anisotropicfill tool paths for at least the first sequence of parallel shells. 5.The 3D printer according to claim 1, wherein the controller is furtherconfigured to control the motorized drive, the anisotropic depositionhead and the isotropic solidifying head to build the 3D printed part bysolidifying the anisotropic fill material in fiber swaths tracking aninner concentric set of anisotropic fill tool paths for at least one ofthe first or second sequence of parallel shells, the inner concentricset of anisotropic tool paths being located surrounding one or morenegative contours or through hole within the 3D printed part.
 6. The 3Dprinter according to claim 1, wherein the controller is furtherconfigured to control the motorized drive, the anisotropic depositionhead and the isotropic solidifying head to build the 3D printed part bysolidifying the anisotropic fill material in fiber swaths tracking aninner concentric set of anisotropic fill tool paths for at least one ofthe first or second sequence of parallel shells, the inner concentricset of anisotropic tool paths being located looping an envelope shapeincluding at least two or more negative contours or through holes withinthe 3D printed part.
 7. The 3D printer according to claim 1, wherein thecontroller is further configured to control the motorized drive, theanisotropic deposition head and the isotropic solidifying head to buildthe 3D printed part by solidifying the anisotropic fill material infiber swaths tracking a cellular infill pattern of anisotropic fill toolpaths for at least one of the first or second sequence of parallelshells, the cellular infill pattern of anisotropic tool paths formingrepeating and cellular walls of anisotropic fill material within the 3Dprinted part.
 8. The 3D printer according to claim 1, wherein thecontroller is further configured to control the motorized drive, theanisotropic deposition head and the isotropic solidifying head to buildthe 3D printed part by solidifying the anisotropic fill material infiber swaths tracking a self-crossing pattern of anisotropic fill toolpaths for at least one of the first or second sequence of parallelshells, the self-crossing pattern of anisotropic tool paths overlappinganisotropic solidification of fiber swaths within a same shell or layer.